From: Kurt Zeilenga Date: Thu, 27 Dec 2001 01:09:58 +0000 (+0000) Subject: Trim RFCs X-Git-Tag: LDBM_PRE_GIANT_RWLOCK~463 X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=02700a4f149674962c82f0e3236ed970b3b4e61f;p=openldap Trim RFCs --- diff --git a/doc/rfc/INDEX b/doc/rfc/INDEX index 358de929ba..2765487d27 100644 --- a/doc/rfc/INDEX +++ b/doc/rfc/INDEX @@ -7,9 +7,7 @@ rfc1617.txt Naming and Structuring Guidelines for X.500 Directory Pilots (I) rfc1798.txt Connection-less LDAP (PS) rfc1823.txt LDAP C API (I) rfc2079.txt X.500 Attribute Type and an Object Class to Hold URIs (PS) -rfc2164.txt X.500/LDAP MIXER address mapping (PS) rfc2218.txt Common Schema for the Internet White Pages Service (PS) -rfc2222.txt Simple Authentication and Security Layer (PS) rfc2247.txt Using Domains in LDAP DNs (PS) rfc2251.txt LDAPv3 Protocol (PS) rfc2252.txt LDAPv3 Attribute Types (PS) @@ -17,7 +15,6 @@ rfc2253.txt LDAPv3 Disinguished Name (PS) rfc2254.txt LDAPv3 Search Filters (PS) rfc2255.txt LDAPv3 URL Format (PS) rfc2256.txt X.500(96) Schema for LDAPv3 (PS) -rfc2279.txt UTF-8 (DS) rfc2293.txt Tables and Subtrees in the X.500 Directory (PS) rfc2294.txt O/R Address hierarchy in the X.500 DIT (PS) rfc2307.txt LDAP Network Information Services Schema (E) @@ -31,7 +28,6 @@ rfc2696.txt LDAP Simple Paged Result Control (I) rfc2713.txt LDAP Java schema (I) rfc2714.txt LDAP CORBA schema (I) rfc2798.txt LDAP inetOrgPerson schema (I) -rfc2828.txt Internet Security Glossary (FYI) rfc2829.txt LDAPv3: Authentication Method (PS) rfc2830.txt LDAPv3: StartTLS (PS) rfc2831.txt SASL/DIGEST-MD5 (PS) diff --git a/doc/rfc/rfc2164.txt b/doc/rfc/rfc2164.txt deleted file mode 100644 index 21270d52ef..0000000000 --- a/doc/rfc/rfc2164.txt +++ /dev/null @@ -1,563 +0,0 @@ - - - - - - -Network Working Group S. Kille -Request for Comments: 2164 Isode Ltd. -Obsoletes: 1838 January 1998 -Category: Standards Track - - - - Use of an X.500/LDAP directory to support MIXER address mapping - -Status of this Memo - - This document specifies an Internet standards track protocol for the - Internet community, and requests discussion and suggestions for - improvements. Please refer to the current edition of the "Internet - Official Protocol Standards" (STD 1) for the standardization state - and status of this protocol. Distribution of this memo is unlimited. - -Copyright Notice - - Copyright (C) The Internet Society (1998). All Rights Reserved. - -1 MIXER X.400/RFC 822 Mappings - - MIXER (RFC 2156) defines an algorithm for use of a set of global - mapping between X.400 and RFC 822 addresses [4]. This specification - defines how to represent and maintain these mappings (MIXER - Conformant Global Address Mappings of MCGAMs) in an X.500 or LDAP - directory. Mechanisms for representing OR Address and Domain - hierarchies within the DIT are defined in [5, 2]. These techniques - are used to define two independent subtrees in the DIT, which contain - the mapping information. The benefits of this approach are: - - 1. The mapping information is kept in a clearly defined area which - can be widely replicated in an efficient manner. The tree is - constrained to hold only information needed to support the - mapping. This is important as gateways need good access to the - entire mapping. - - 2. It facilitates migration from a table-based approach. - - 3. It handles the issues of "missing components" in a natural - manner. - - An alternative approach which is not taken is to locate the - information in the routing subtrees. The benefits of this - would be: - - - - - -Kille Standards Track [Page 1] - -RFC 2164 X.500/LDAP Directory to Support MIXER January 1998 - - - o It is the "natural" location, and will also help to - ensure correct administrative authority for a mapping - definition. - - o The tree will usually be accessed for routing, and so it - will be efficient for addresses which are being routed. - - This is not done, as the benefits of the approach proposed are - greater. - - MCGAMs are global. A MIXER gateway may use any set of MCGAMs. A key - use of the directory is to enable MIXER gateways to share MCGAMs and - to share the effort of maintaining and publishing MCGAMs. This - specification and MIXER also recognise that there is not a single - unique location for publication of all MCGAMs. This specification - allows for multiple sets of MCGAMs to be published. Each set of - MCGAMs is published under a single part of the directory. There are - four mappings, which are represented by two subtrees located under - any part of the DIT. For the examples the location defined below is - used: - - - OU=MIXER MCGAMs, O=Zydeco Plc, C=GB - - These subtree roots are of object class subtree, and use the - mechanism for representing subtrees defined in [1]. - - - X.400 to RFC 822 This table gives the equivalence mapping from X.400 - to RFC 822. There is an OR Address tree under this. An example - entry is: - - PRMD=Isode, ADMD=Mailnet, C=FI, CN=X.400 to RFC 822, - OU=MIXER MCGAMs, O=Zydeco Plc, C=GB - - RFC 822 to X.400 There is a domain tree under this. This table holds - the equivalence mapping from RFC 822 to X.400, and the gateway - mapping defined in RFC 1327. An example entry is: - - DomainComponent=ISODE, DomainComponent=COM, - CN=RFC 822 to X.400, - OU=MIXER MCGAMs, O=Zydeco Plc, C=GB - - The values of the table mapping are defined by use of two new object - classes, as specified in Figure 1. The objects give pointers to the - mapped components. - - - - - -Kille Standards Track [Page 2] - -RFC 2164 X.500/LDAP Directory to Support MIXER January 1998 - - -2 Omitted Components - - In MIXER, it is possible to have omitted components in OR Addresses - on either side of the mapping. A mechanism to represent such omitted - components is defined in Figure 2. The attribute at-or-address- - component-type is set to the X.500 attribute type associated with the - omitted component (e.g., - - -rFC822ToX400Mapping OBJECT-CLASS ::= { - SUBCLASS OF {domain-component} - MAY CONTAIN { - associatedORAddress| - associatedX400Gateway} - ID oc-rfc822-to-x400-mapping} - -x400ToRFC822Mapping OBJECT-CLASS ::= { - SUBCLASS OF {top} - MAY CONTAIN { 10 - associatedDomain| - associatedInternetGateway} - ID oc-x400-to-rfc822-mapping} - -associatedORAddress ATTRIBUTE ::= { - SUBTYPE OF distinguishedName - SINGLE VALUE - ID at-associated-or-address} - - 20 -associatedX400Gateway ATTRIBUTE ::= { - SUBTYPE OF mhs-or-addresses - MULTI VALUE - ID at-associated-x400-gateway} - -associatedDomain ATTRIBUTE ::= { - SUBTYPE OF name - WITH SYNTAX caseIgnoreIA5String - SINGLE VALUE - ID at-associated-domain} 30 - -associatedInternetGateway ATTRIBUTE ::= { - SUBTYPE OF name - WITH SYNTAX caseIgnoreIA5String - MULTI VALUE - ID at-associated-internet-gateway} - - - Figure 1: Object Classes for MIXER mappings - - - -Kille Standards Track [Page 3] - -RFC 2164 X.500/LDAP Directory to Support MIXER January 1998 - - -omittedORAddressComponent OBJECT-CLASS ::= - SUBCLASS OF {top} - MUST Contain { - oRAddressComponentType - } - ID oc-omitted-or-address-component} - - -oRAddressComponentType ATTRIBUTE ::= { - SUBTYPE OF objectIdentifier 10 - SINGLE VALUE - ID at-or-address-component-type} - - Figure 2: Omitted OR Address Component - - - at-prmd-name). This mechanism is for use only within the X.400 to - RFC 822 subtree and for the at-associated-or-address attribute. - -3 Mapping from X.400 to RFC 822 - - As an example, consider the mapping from the OR Address: - - - P=Isode; A=Mailnet; C=FI - - This would be keyed by the directory entry: - - PRMD=Isode, ADMD=Mailnet, C=FI, CN=X.400 to RFC 822, - OU=MIXER MCGAMs, O=Zydeco Plc, C=GB - - and return the mapping from the associatedDomain attribute, which - gives the domain which this OR address maps to. This attribute is - used to define authoritative mappings, which are placed in the open - community tree. The manager of an MCGAM shall make the appropriate - entry. - - The Internet gateway mapping defined in MIXER[4] is provided by the - associatedInternetGateway attribute. This value may identify - multiple possible associated gateways. This information is looked up - at the same time as mapped OR addresses. In effect, this provides a - fallback mapping, which is found if there is no equivalence mapping. - Because of the nature of the mapping an OR Address will map to either - a gateway or a domain, but not both. Thus, there shall never be both - - - - - - - -Kille Standards Track [Page 4] - -RFC 2164 X.500/LDAP Directory to Support MIXER January 1998 - - - an associatedDomain and associatedInternetGateway attribute present - in the same entry. Functionally, mapping takes place exactly - according to MIXER. The longest match is found by the following - algorithm. - - 1. Take the OR Address, and derive a directory name. This will be - the OR Address as far as the lowest OU. - - 2. Look up the entire name derived from the MIXER key in the in the - X.400 to RFC 822 subtree. This lookup will either succeed, or it - will fail and indicate the longest possible match, which can then - be looked up. - - 3. Check for an associatedDomain or associatedInternetGateway - attribute in the matched entry. - - The mapping can always be achieved with two lookups. Because of the - availability of aliases, some of the table mappings may be - simplified. In addition, the directory can support mapping from - addresses using the numeric country codes. - -4 Mapping from RFC 822 to X.400 - - There is an analogous structure for mappings in the reverse - direction. The domain hierarchy is represented in the DIT according - to RFC 1279. The domain: - - ISODE.COM - - Is represented in the DIT as: - - DomainComponent=ISODE, DomainComponent=COM, CN=RFC 822 to X.400, - OU=MIXER MCGAMs, O=Zydeco Plc, C=GB - - This has associated with it the attribute associatedORAddress encoded - as a distinguished name with a value: PRMD=Isode, ADMD=Mailnet, C=FI - - The X.400 gateway mapping defined in MIXER[4] is provided by the - associatedX400Gateway attribute. This value may identify multiple - possible associated gateways. This information is looked up at the - same time as mapped OR addresses. In effect, this provides a - fallback mapping, which is found if there is no equivalence mapping. - Because of the nature of the mapping a domain will map to either a - gateway or a domain, but not both. Thus, there shall never be both - an associatedX400Gateway and associatedORAddress attribute present in - the same entry. Functionally, mapping takes place exactly according - to MIXER. The longest match is found by the following algorithm. - - - - -Kille Standards Track [Page 5] - -RFC 2164 X.500/LDAP Directory to Support MIXER January 1998 - - - 1. Derive a directory name from the domain part of the RFC 822 - address. - - 2. Look up this name in the RFC 822 to X.400 subtree to find the - mapped value (either associatedORAddress or - associatedX400Gateway.). If the lookup fails, the error will - indicate the longest match, which can then be looked up. - - If associatedORAddress is found, this will define the mapped OR - Address. The mapping can always be achieved with two lookups. If an - associatedX400Gateway is present, the address in question will be - encoded as a domain defined attribute, relative to the OR Address - defined by this attribute. If multiple associatedX400Gateway - attributes are found, the MTA may select the one it chooses to use. - - Because of the availability of aliases, some of the table mappings - may be simplified. In addition, the directory can support mapping - from addresses using the numeric country codes. - -5 Gateway Selection of MCGAMs - - The directory information to support identification of MCGAMs is - given in Figure 3. A MIXER gateway simply identifies the an ordered - lists of MCGAM collections that it will use for lookup. These are - referenced by name. A gateway is not required to use any MCGAMs. - Where MCGAMs are accessed from multiple sources, it is recommended - that all of the sources be accessed in order to determine the MCGAM - which gives the - - -mixerGateway OBJECT-CLASS ::= - KIND auxiliary - SUBCLASS OF {mhs-message-transfer-agent} - MUST Contain { - mcgamTables - } - ID oc-mixer-gateway} - - -mcgamTables ATTRIBUTE ::= { 10 - WITH SYNTAX SEQUENCE OF DistinguishedName - SINGLE VALUE - ID at-mcgam-tables} - - Figure 3: Object Classes for MCGAM selection - - -best match. - - - -Kille Standards Track [Page 6] - -RFC 2164 X.500/LDAP Directory to Support MIXER January 1998 - - -6 Acknowledgements - - Acknowledgements for work on this document are given in [3]. - -References - - [1] Kille, S., "Representing tables and subtrees in the X.500 - directory", RFC 1837, August 1995. - - [2] Kille, S., "Representing the O/R Address hierarchy in the X.500 - directory information tree," RFC 1836, August 1995. - - [3] Kille, S., " X.400-MHS use of the X.500 directory to support - X.400-MHS routing," RFC 1801, June 1995. - - [4] Kille, S., "MIXER (Mime Internet X.400 Enhanced Relay): - Mapping between X.400 and RFC 822/MIME," RFC 2156, January 1998. - - [5] Kille, S., Wahl, M., Grimsatd, A., Huber, R., and S. Sataluri, - "Using Domains in LDAP/X.500 Distinguished Names", RFC 2247, - January 1998. - -7 Security Considerations - - This document specifies a means by which the X.500/LDAP directory - service can direct the translation between X.400 and Internet mail - addresses. This can indirectly affect the routing of messages across - a gateway between X.400 and Internet Mail. A succesful attack on - this service could cause incorrect translation of an originator - address (thus "forging" the originator address), or incorrect - translation of a recipient address (thus directing the mail to an - unauthorized recipient, or making it appear to an authorized - recipient, that the message was intended for recipients other than - those chosen by the originator). When cryptographic authentication - is available for directory responses, clients shall employ those - mechanisms to verify the authenticity and integrity of those - responses. - - - - - - - - - - - - - - -Kille Standards Track [Page 7] - -RFC 2164 X.500/LDAP Directory to Support MIXER January 1998 - - -8 Author's Address - - Steve Kille - Isode Ltd. - The Dome - The Square - Richmond - TW9 1DT - England - - Phone: +44-181-332-9091 - Internet EMail: S.Kille@ISODE.COM - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Kille Standards Track [Page 8] - -RFC 2164 X.500/LDAP Directory to Support MIXER January 1998 - - -A Object Identifier Assignment - - -mhs-ds OBJECT IDENTIFIER ::= {iso(1) org(3) dod(6) internet(1) private(4) - enterprises(1) isode-consortium (453) mhs-ds (7)} - -mapping OBJECT IDENTIFIER ::= {mhs-ds 4} - -oc OBJECT IDENTIFIER ::= {mapping 1} -at OBJECT IDENTIFIER ::= {mapping 2} - - -oc-rfc822-to-x400-mapping OBJECT IDENTIFIER ::= {oc 1} 10 -oc-x400-to-rfc822-mapping OBJECT IDENTIFIER ::= {oc 2} -oc-omitted-or-address-component OBJECT IDENTIFIER ::= {oc 3} -oc-mixer-gateway ::= {oc 4} - -at-associated-or-address OBJECT IDENTIFIER ::= {at 6} -at-associated-x400-gateway OBJECT IDENTIFIER ::= {at 3} -at-associated-domain OBJECT IDENTIFIER ::= {at 4} -at-or-address-component-type OBJECT IDENTIFIER ::= {at 7} -at-associated-internet-gateway OBJECT IDENTIFIER ::= {at 8} -at-mcgam-tables ::= {at 9} 20 - - - Figure 4: Object Identifier Assignment - - - - - - - - - - - - - - - - - - - - - - - - - -Kille Standards Track [Page 9] - -RFC 2164 X.500/LDAP Directory to Support MIXER January 1998 - - -Full Copyright Statement - - Copyright (C) The Internet Society (1998). All Rights Reserved. - - This document and translations of it may be copied and furnished to - others, and derivative works that comment on or otherwise explain it - or assist in its implementation may be prepared, copied, published - and distributed, in whole or in part, without restriction of any - kind, provided that the above copyright notice and this paragraph are - included on all such copies and derivative works. However, this - document itself may not be modified in any way, such as by removing - the copyright notice or references to the Internet Society or other - Internet organizations, except as needed for the purpose of - developing Internet standards in which case the procedures for - copyrights defined in the Internet Standards process must be - followed, or as required to translate it into languages other than - English. - - The limited permissions granted above are perpetual and will not be - revoked by the Internet Society or its successors or assigns. - - This document and the information contained herein is provided on an - "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING - TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING - BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION - HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF - MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. - - - - - - - - - - - - - - - - - - - - - - - - -Kille Standards Track [Page 10] - diff --git a/doc/rfc/rfc2222.txt b/doc/rfc/rfc2222.txt deleted file mode 100644 index 2b0a2abc10..0000000000 --- a/doc/rfc/rfc2222.txt +++ /dev/null @@ -1,899 +0,0 @@ - - - - - - -Network Working Group J. Myers -Request for Comments: 2222 Netscape Communications -Category: Standards Track October 1997 - - - Simple Authentication and Security Layer (SASL) - -Status of this Memo - - This document specifies an Internet standards track protocol for the - Internet community, and requests discussion and suggestions for - improvements. Please refer to the current edition of the "Internet - Official Protocol Standards" (STD 1) for the standardization state - and status of this protocol. Distribution of this memo is unlimited. - -Copyright Notice - - Copyright (C) The Internet Society (1997). All Rights Reserved. - -Table of Contents - - 1. Abstract .............................................. 2 - 2. Organization of this Document ......................... 2 - 2.1. How to Read This Document ............................. 2 - 2.2. Conventions Used in this Document ..................... 2 - 2.3. Examples .............................................. 3 - 3. Introduction and Overview ............................. 3 - 4. Profiling requirements ................................ 4 - 5. Specific issues ....................................... 5 - 5.1. Client sends data first ............................... 5 - 5.2. Server returns success with additional data ........... 5 - 5.3. Multiple authentications .............................. 5 - 6. Registration procedures ............................... 6 - 6.1. Comments on SASL mechanism registrations .............. 6 - 6.2. Location of Registered SASL Mechanism List ............ 6 - 6.3. Change Control ........................................ 7 - 6.4. Registration Template ................................. 7 - 7. Mechanism definitions ................................. 8 - 7.1. Kerberos version 4 mechanism .......................... 8 - 7.2. GSSAPI mechanism ...................................... 9 - 7.2.1 Client side of authentication protocol exchange ....... 9 - 7.2.2 Server side of authentication protocol exchange ....... 10 - 7.2.3 Security layer ........................................ 11 - 7.3. S/Key mechanism ....................................... 11 - 7.4. External mechanism .................................... 12 - 8. References ............................................ 13 - 9. Security Considerations ............................... 13 - 10. Author's Address ...................................... 14 - - - -Myers Standards Track [Page 1] - -RFC 2222 SASL October 1997 - - - Appendix A. Relation of SASL to Transport Security .......... 15 - Full Copyright Statement .................................... 16 - -1. Abstract - - This document describes a method for adding authentication support to - connection-based protocols. To use this specification, a protocol - includes a command for identifying and authenticating a user to a - server and for optionally negotiating protection of subsequent - protocol interactions. If its use is negotiated, a security layer is - inserted between the protocol and the connection. This document - describes how a protocol specifies such a command, defines several - mechanisms for use by the command, and defines the protocol used for - carrying a negotiated security layer over the connection. - -2. Organization of this Document - -2.1. How to Read This Document - - This document is written to serve two different audiences, protocol - designers using this specification to support authentication in their - protocol, and implementors of clients or servers for those protocols - using this specification. - - The sections "Introduction and Overview", "Profiling requirements", - and "Security Considerations" cover issues that protocol designers - need to understand and address in profiling this specification for - use in a specific protocol. - - Implementors of a protocol using this specification need the - protocol-specific profiling information in addition to the - information in this document. - -2.2. Conventions Used in this Document - - In examples, "C:" and "S:" indicate lines sent by the client and - server respectively. - - The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" - in this document are to be interpreted as defined in "Key words for - use in RFCs to Indicate Requirement Levels" [RFC 2119]. - - - - - - - - - - -Myers Standards Track [Page 2] - -RFC 2222 SASL October 1997 - - -2.3. Examples - - Examples in this document are for the IMAP profile [RFC 2060] of this - specification. The base64 encoding of challenges and responses, as - well as the "+ " preceding the responses are part of the IMAP4 - profile, not part of the SASL specification itself. - -3. Introduction and Overview - - The Simple Authentication and Security Layer (SASL) is a method for - adding authentication support to connection-based protocols. To use - this specification, a protocol includes a command for identifying and - authenticating a user to a server and for optionally negotiating a - security layer for subsequent protocol interactions. - - The command has a required argument identifying a SASL mechanism. - SASL mechanisms are named by strings, from 1 to 20 characters in - length, consisting of upper-case letters, digits, hyphens, and/or - underscores. SASL mechanism names must be registered with the IANA. - Procedures for registering new SASL mechanisms are given in the - section "Registration procedures" - - If a server supports the requested mechanism, it initiates an - authentication protocol exchange. This consists of a series of - server challenges and client responses that are specific to the - requested mechanism. The challenges and responses are defined by the - mechanisms as binary tokens of arbitrary length. The protocol's - profile then specifies how these binary tokens are then encoded for - transfer over the connection. - - After receiving the authentication command or any client response, a - server may issue a challenge, indicate failure, or indicate - completion. The protocol's profile specifies how the server - indicates which of the above it is doing. - - After receiving a challenge, a client may issue a response or abort - the exchange. The protocol's profile specifies how the client - indicates which of the above it is doing. - - During the authentication protocol exchange, the mechanism performs - authentication, transmits an authorization identity (frequently known - as a userid) from the client to server, and negotiates the use of a - mechanism-specific security layer. If the use of a security layer is - agreed upon, then the mechanism must also define or negotiate the - maximum cipher-text buffer size that each side is able to receive. - - - - - - -Myers Standards Track [Page 3] - -RFC 2222 SASL October 1997 - - - The transmitted authorization identity may be different than the - identity in the client's authentication credentials. This permits - agents such as proxy servers to authenticate using their own - credentials, yet request the access privileges of the identity for - which they are proxying. With any mechanism, transmitting an - authorization identity of the empty string directs the server to - derive an authorization identity from the client's authentication - credentials. - - If use of a security layer is negotiated, it is applied to all - subsequent data sent over the connection. The security layer takes - effect immediately following the last response of the authentication - exchange for data sent by the client and the completion indication - for data sent by the server. Once the security layer is in effect, - the protocol stream is processed by the security layer into buffers - of cipher-text. Each buffer is transferred over the connection as a - stream of octets prepended with a four octet field in network byte - order that represents the length of the following buffer. The length - of the cipher-text buffer must be no larger than the maximum size - that was defined or negotiated by the other side. - -4. Profiling requirements - - In order to use this specification, a protocol definition must supply - the following information: - - 1. A service name, to be selected from the IANA registry of "service" - elements for the GSSAPI host-based service name form [RFC 2078]. - - 2. A definition of the command to initiate the authentication - protocol exchange. This command must have as a parameter the - mechanism name being selected by the client. - - The command SHOULD have an optional parameter giving an initial - response. This optional parameter allows the client to avoid a - round trip when using a mechanism which is defined to have the - client send data first. When this initial response is sent by the - client and the selected mechanism is defined to have the server - start with an initial challenge, the command fails. See section - 5.1 of this document for further information. - - 3. A definition of the method by which the authentication protocol - exchange is carried out, including how the challenges and - responses are encoded, how the server indicates completion or - failure of the exchange, how the client aborts an exchange, and - how the exchange method interacts with any line length limits in - the protocol. - - - - -Myers Standards Track [Page 4] - -RFC 2222 SASL October 1997 - - - 4. Identification of the octet where any negotiated security layer - starts to take effect, in both directions. - - 5. A specification of how the authorization identity passed from the - client to the server is to be interpreted. - -5. Specific issues - -5.1. Client sends data first - - Some mechanisms specify that the first data sent in the - authentication protocol exchange is from the client to the server. - - If a protocol's profile permits the command which initiates an - authentication protocol exchange to contain an initial client - response, this parameter SHOULD be used with such mechanisms. - - If the initial client response parameter is not given, or if a - protocol's profile does not permit the command which initiates an - authentication protocol exchange to contain an initial client - response, then the server issues a challenge with no data. The - client's response to this challenge is then used as the initial - client response. (The server then proceeds to send the next - challenge, indicates completion, or indicates failure.) - -5.2. Server returns success with additional data - - Some mechanisms may specify that server challenge data be sent to the - client along with an indication of successful completion of the - exchange. This data would, for example, authenticate the server to - the client. - - If a protocol's profile does not permit this server challenge to be - returned with a success indication, then the server issues the server - challenge without an indication of successful completion. The client - then responds with no data. After receiving this empty response, the - server then indicates successful completion. - -5.3. Multiple authentications - - Unless otherwise stated by the protocol's profile, only one - successful SASL negotiation may occur in a protocol session. In this - case, once an authentication protocol exchange has successfully - completed, further attempts to initiate an authentication protocol - exchange fail. - - - - - - -Myers Standards Track [Page 5] - -RFC 2222 SASL October 1997 - - - In the case that a profile explicitly permits multiple successful - SASL negotiations to occur, then in no case may multiple security - layers be simultaneously in effect. If a security layer is in effect - and a subsequent SASL negotiation selects no security layer, the - original security layer remains in effect. If a security layer is in - effect and a subsequent SASL negotiation selects a second security - layer, then the second security layer replaces the first. - -6. Registration procedures - - Registration of a SASL mechanism is done by filling in the template - in section 6.4 and sending it in to iana@isi.edu. IANA has the right - to reject obviously bogus registrations, but will perform no review - of clams made in the registration form. - - There is no naming convention for SASL mechanisms; any name that - conforms to the syntax of a SASL mechanism name can be registered. - - While the registration procedures do not require it, authors of SASL - mechanisms are encouraged to seek community review and comment - whenever that is feasible. Authors may seek community review by - posting a specification of their proposed mechanism as an internet- - draft. SASL mechanisms intended for widespread use should be - standardized through the normal IETF process, when appropriate. - -6.1. Comments on SASL mechanism registrations - - Comments on registered SASL mechanisms should first be sent to the - "owner" of the mechanism. Submitters of comments may, after a - reasonable attempt to contact the owner, request IANA to attach their - comment to the SASL mechanism registration itself. If IANA approves - of this the comment will be made accessible in conjunction with the - SASL mechanism registration itself. - -6.2. Location of Registered SASL Mechanism List - - SASL mechanism registrations will be posted in the anonymous FTP - directory "ftp://ftp.isi.edu/in-notes/iana/assignments/sasl- - mechanisms/" and all registered SASL mechanisms will be listed in the - periodically issued "Assigned Numbers" RFC [currently STD 2, RFC - 1700]. The SASL mechanism description and other supporting material - may also be published as an Informational RFC by sending it to "rfc- - editor@isi.edu" (please follow the instructions to RFC authors [RFC - 2223]). - - - - - - - -Myers Standards Track [Page 6] - -RFC 2222 SASL October 1997 - - -6.3. Change Control - - Once a SASL mechanism registration has been published by IANA, the - author may request a change to its definition. The change request - follows the same procedure as the registration request. - - The owner of a SASL mechanism may pass responsibility for the SASL - mechanism to another person or agency by informing IANA; this can be - done without discussion or review. - - The IESG may reassign responsibility for a SASL mechanism. The most - common case of this will be to enable changes to be made to - mechanisms where the author of the registration has died, moved out - of contact or is otherwise unable to make changes that are important - to the community. - - SASL mechanism registrations may not be deleted; mechanisms which are - no longer believed appropriate for use can be declared OBSOLETE by a - change to their "intended use" field; such SASL mechanisms will be - clearly marked in the lists published by IANA. - - The IESG is considered to be the owner of all SASL mechanisms which - are on the IETF standards track. - -6.4. Registration Template - - To: iana@iana.org - Subject: Registration of SASL mechanism X - - SASL mechanism name: - - Security considerations: - - Published specification (optional, recommended): - - Person & email address to contact for further information: - - Intended usage: - - (One of COMMON, LIMITED USE or OBSOLETE) - - Author/Change controller: - - (Any other information that the author deems interesting may be - added below this line.) - - - - - - -Myers Standards Track [Page 7] - -RFC 2222 SASL October 1997 - - -7. Mechanism definitions - - The following mechanisms are hereby defined. - -7.1. Kerberos version 4 mechanism - - The mechanism name associated with Kerberos version 4 is - "KERBEROS_V4". - - The first challenge consists of a random 32-bit number in network - byte order. The client responds with a Kerberos ticket and an - authenticator for the principal "service.hostname@realm", where - "service" is the service name specified in the protocol's profile, - "hostname" is the first component of the host name of the server with - all letters in lower case, and where "realm" is the Kerberos realm of - the server. The encrypted checksum field included within the - Kerberos authenticator contains the server provided challenge in - network byte order. - - Upon decrypting and verifying the ticket and authenticator, the - server verifies that the contained checksum field equals the original - server provided random 32-bit number. Should the verification be - successful, the server must add one to the checksum and construct 8 - octets of data, with the first four octets containing the incremented - checksum in network byte order, the fifth octet containing a bit-mask - specifying the security layers supported by the server, and the sixth - through eighth octets containing, in network byte order, the maximum - cipher-text buffer size the server is able to receive. The server - must encrypt using DES ECB mode the 8 octets of data in the session - key and issue that encrypted data in a second challenge. The client - considers the server authenticated if the first four octets of the - un-encrypted data is equal to one plus the checksum it previously - sent. - - The client must construct data with the first four octets containing - the original server-issued checksum in network byte order, the fifth - octet containing the bit-mask specifying the selected security layer, - the sixth through eighth octets containing in network byte order the - maximum cipher-text buffer size the client is able to receive, and - the following octets containing the authorization identity. The - client must then append from one to eight zero-valued octets so that - the length of the data is a multiple of eight octets. The client must - then encrypt using DES PCBC mode the data with the session key and - respond with the encrypted data. The server decrypts the data and - verifies the contained checksum. The server must verify that the - principal identified in the Kerberos ticket is authorized to connect - as that authorization identity. After this verification, the - authentication process is complete. - - - -Myers Standards Track [Page 8] - -RFC 2222 SASL October 1997 - - - The security layers and their corresponding bit-masks are as follows: - - 1 No security layer - 2 Integrity (krb_mk_safe) protection - 4 Privacy (krb_mk_priv) protection - - Other bit-masks may be defined in the future; bits which are not - understood must be negotiated off. - - EXAMPLE: The following are two Kerberos version 4 login scenarios to - the IMAP4 protocol (note that the line breaks in the sample - authenticators are for editorial clarity and are not in real - authenticators) - - S: * OK IMAP4 Server - C: A001 AUTHENTICATE KERBEROS_V4 - S: + AmFYig== - C: BAcAQU5EUkVXLkNNVS5FRFUAOCAsho84kLN3/IJmrMG+25a4DT - +nZImJjnTNHJUtxAA+o0KPKfHEcAFs9a3CL5Oebe/ydHJUwYFd - WwuQ1MWiy6IesKvjL5rL9WjXUb9MwT9bpObYLGOKi1Qh - S: + or//EoAADZI= - C: DiAF5A4gA+oOIALuBkAAmw== - S: A001 OK Kerberos V4 authentication successful - - - S: * OK IMAP4 Server - C: A001 AUTHENTICATE KERBEROS_V4 - S: + gcfgCA== - C: BAcAQU5EUkVXLkNNVS5FRFUAOCAsho84kLN3/IJmrMG+25a4DT - +nZImJjnTNHJUtxAA+o0KPKfHEcAFs9a3CL5Oebe/ydHJUwYFd - WwuQ1MWiy6IesKvjL5rL9WjXUb9MwT9bpObYLGOKi1Qh - S: A001 NO Kerberos V4 authentication failed - -7.2. GSSAPI mechanism - - The mechanism name associated with all mechanisms employing the - GSSAPI [RFC 2078] is "GSSAPI". - -7.2.1 Client side of authentication protocol exchange - - The client calls GSS_Init_sec_context, passing in 0 for - input_context_handle (initially) and a targ_name equal to output_name - from GSS_Import_Name called with input_name_type of - GSS_C_NT_HOSTBASED_SERVICE and input_name_string of - "service@hostname" where "service" is the service name specified in - the protocol's profile, and "hostname" is the fully qualified host - name of the server. The client then responds with the resulting - output_token. If GSS_Init_sec_context returns GSS_S_CONTINUE_NEEDED, - - - -Myers Standards Track [Page 9] - -RFC 2222 SASL October 1997 - - - then the client should expect the server to issue a token in a - subsequent challenge. The client must pass the token to another call - to GSS_Init_sec_context, repeating the actions in this paragraph. - - When GSS_Init_sec_context returns GSS_S_COMPLETE, the client takes - the following actions: If the last call to GSS_Init_sec_context - returned an output_token, then the client responds with the - output_token, otherwise the client responds with no data. The client - should then expect the server to issue a token in a subsequent - challenge. The client passes this token to GSS_Unwrap and interprets - the first octet of resulting cleartext as a bit-mask specifying the - security layers supported by the server and the second through fourth - octets as the maximum size output_message to send to the server. The - client then constructs data, with the first octet containing the - bit-mask specifying the selected security layer, the second through - fourth octets containing in network byte order the maximum size - output_message the client is able to receive, and the remaining - octets containing the authorization identity. The client passes the - data to GSS_Wrap with conf_flag set to FALSE, and responds with the - generated output_message. The client can then consider the server - authenticated. - -7.2.2 Server side of authentication protocol exchange - - The server passes the initial client response to - GSS_Accept_sec_context as input_token, setting input_context_handle - to 0 (initially). If GSS_Accept_sec_context returns - GSS_S_CONTINUE_NEEDED, the server returns the generated output_token - to the client in challenge and passes the resulting response to - another call to GSS_Accept_sec_context, repeating the actions in this - paragraph. - - When GSS_Accept_sec_context returns GSS_S_COMPLETE, the client takes - the following actions: If the last call to GSS_Accept_sec_context - returned an output_token, the server returns it to the client in a - challenge and expects a reply from the client with no data. Whether - or not an output_token was returned (and after receipt of any - response from the client to such an output_token), the server then - constructs 4 octets of data, with the first octet containing a bit- - mask specifying the security layers supported by the server and the - second through fourth octets containing in network byte order the - maximum size output_token the server is able to receive. The server - must then pass the plaintext to GSS_Wrap with conf_flag set to FALSE - and issue the generated output_message to the client in a challenge. - The server must then pass the resulting response to GSS_Unwrap and - interpret the first octet of resulting cleartext as the bit-mask for - the selected security layer, the second through fourth octets as the - maximum size output_message to send to the client, and the remaining - - - -Myers Standards Track [Page 10] - -RFC 2222 SASL October 1997 - - - octets as the authorization identity. The server must verify that - the src_name is authorized to authenticate as the authorization - identity. After these verifications, the authentication process is - complete. - -7.2.3 Security layer - - The security layers and their corresponding bit-masks are as follows: - - 1 No security layer - 2 Integrity protection. - Sender calls GSS_Wrap with conf_flag set to FALSE - 4 Privacy protection. - Sender calls GSS_Wrap with conf_flag set to TRUE - - Other bit-masks may be defined in the future; bits which are not - understood must be negotiated off. - -7.3. S/Key mechanism - - The mechanism name associated with S/Key [RFC 1760] using the MD4 - digest algorithm is "SKEY". - - The client sends an initial response with the authorization identity. - - The server then issues a challenge which contains the decimal - sequence number followed by a single space and the seed string for - the indicated authorization identity. The client responds with the - one-time-password, as either a 64-bit value in network byte order or - encoded in the "six English words" format. - - The server must verify the one-time-password. After this - verification, the authentication process is complete. - - S/Key authentication does not provide for any security layers. - - EXAMPLE: The following are two S/Key login scenarios in the IMAP4 - protocol. - - S: * OK IMAP4 Server - C: A001 AUTHENTICATE SKEY - S: + - C: bW9yZ2Fu - S: + OTUgUWE1ODMwOA== - C: Rk9VUiBNQU5OIFNPT04gRklSIFZBUlkgTUFTSA== - S: A001 OK S/Key authentication successful - - - - - -Myers Standards Track [Page 11] - -RFC 2222 SASL October 1997 - - - S: * OK IMAP4 Server - C: A001 AUTHENTICATE SKEY - S: + - C: c21pdGg= - S: + OTUgUWE1ODMwOA== - C: BsAY3g4gBNo= - S: A001 NO S/Key authentication failed - - The following is an S/Key login scenario in an IMAP4-like protocol - which has an optional "initial response" argument to the AUTHENTICATE - command. - - S: * OK IMAP4-Like Server - C: A001 AUTHENTICATE SKEY bW9yZ2Fu - S: + OTUgUWE1ODMwOA== - C: Rk9VUiBNQU5OIFNPT04gRklSIFZBUlkgTUFTSA== - S: A001 OK S/Key authentication successful - -7.4. External mechanism - - The mechanism name associated with external authentication is - "EXTERNAL". - - The client sends an initial response with the authorization identity. - - The server uses information, external to SASL, to determine whether - the client is authorized to authenticate as the authorization - identity. If the client is so authorized, the server indicates - successful completion of the authentication exchange; otherwise the - server indicates failure. - - The system providing this external information may be, for example, - IPsec or TLS. - - If the client sends the empty string as the authorization identity - (thus requesting the authorization identity be derived from the - client's authentication credentials), the authorization identity is - to be derived from authentication credentials which exist in the - system which is providing the external authentication. - - - - - - - - - - - - -Myers Standards Track [Page 12] - -RFC 2222 SASL October 1997 - - -8. References - - [RFC 2060] Crispin, M., "Internet Message Access Protocol - Version - 4rev1", RFC 2060, December 1996. - - [RFC 2078] Linn, J., "Generic Security Service Application Program - Interface, Version 2", RFC 2078, January 1997. - - [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate - Requirement Levels", RFC 2119, March 1997. - - [RFC 2223] Postel, J., and J. Reynolds, "Instructions to RFC - Authors", RFC 2223, October 1997. - - [RFC 1760] Haller, N., "The S/Key One-Time Password System", RFC - 1760, February 1995. - - [RFC 1700] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2, - RFC 1700, October 1994. - -9. Security Considerations - - Security issues are discussed throughout this memo. - - The mechanisms that support integrity protection are designed such - that the negotiation of the security layer and authorization identity - is integrity protected. When the client selects a security layer - with at least integrity protection, this protects against an active - attacker hijacking the connection and modifying the authentication - exchange to negotiate a plaintext connection. - - When a server or client supports multiple authentication mechanisms, - each of which has a different security strength, it is possible for - an active attacker to cause a party to use the least secure mechanism - supported. To protect against this sort of attack, a client or - server which supports mechanisms of different strengths should have a - configurable minimum strength that it will use. It is not sufficient - for this minimum strength check to only be on the server, since an - active attacker can change which mechanisms the client sees as being - supported, causing the client to send authentication credentials for - its weakest supported mechanism. - - - - - - - - - - -Myers Standards Track [Page 13] - -RFC 2222 SASL October 1997 - - - The client's selection of a SASL mechanism is done in the clear and - may be modified by an active attacker. It is important for any new - SASL mechanisms to be designed such that an active attacker cannot - obtain an authentication with weaker security properties by modifying - the SASL mechanism name and/or the challenges and responses. - - Any protocol interactions prior to authentication are performed in - the clear and may be modified by an active attacker. In the case - where a client selects integrity protection, it is important that any - security-sensitive protocol negotiations be performed after - authentication is complete. Protocols should be designed such that - negotiations performed prior to authentication should be either - ignored or revalidated once authentication is complete. - -10. Author's Address - - John G. Myers - Netscape Communications - 501 E. Middlefield Road - Mail Stop MV-029 - Mountain View, CA 94043-4042 - - EMail: jgmyers@netscape.com - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Myers Standards Track [Page 14] - -RFC 2222 SASL October 1997 - - -Appendix A. Relation of SASL to Transport Security - - Questions have been raised about the relationship between SASL and - various services (such as IPsec and TLS) which provide a secured - connection. - - Two of the key features of SASL are: - - 1. The separation of the authorization identity from the identity in - the client's credentials. This permits agents such as proxy - servers to authenticate using their own credentials, yet request - the access privileges of the identity for which they are proxying. - - 2. Upon successful completion of an authentication exchange, the - server knows the authorization identity the client wishes to use. - This allows servers to move to a "user is authenticated" state in - the protocol. - - These features are extremely important to some application protocols, - yet Transport Security services do not always provide them. To - define SASL mechanisms based on these services would be a very messy - task, as the framing of these services would be redundant with the - framing of SASL and some method of providing these important SASL - features would have to be devised. - - Sometimes it is desired to enable within an existing connection the - use of a security service which does not fit the SASL model. (TLS is - an example of such a service.) This can be done by adding a command, - for example "STARTTLS", to the protocol. Such a command is outside - the scope of SASL, and should be different from the command which - starts a SASL authentication protocol exchange. - - In certain situations, it is reasonable to use SASL underneath one of - these Transport Security services. The transport service would - secure the connection, either service would authenticate the client, - and SASL would negotiate the authorization identity. The SASL - negotiation would be what moves the protocol from "unauthenticated" - to "authenticated" state. The "EXTERNAL" SASL mechanism is - explicitly intended to handle the case where the transport service - secures the connection and authenticates the client and SASL - negotiates the authorization identity. - - When using SASL underneath a sufficiently strong Transport Security - service, a SASL security layer would most likely be redundant. The - client and server would thus probably want to negotiate off the use - of a SASL security layer. - - - - - -Myers Standards Track [Page 15] - -RFC 2222 SASL October 1997 - - -Full Copyright Statement - - Copyright (C) The Internet Society (1997). All Rights Reserved. - - This document and translations of it may be copied and furnished to - others, and derivative works that comment on or otherwise explain it - or assist in its implmentation may be prepared, copied, published - andand distributed, in whole or in part, without restriction of any - kind, provided that the above copyright notice and this paragraph are - included on all such copies and derivative works. However, this - document itself may not be modified in any way, such as by removing - the copyright notice or references to the Internet Society or other - Internet organizations, except as needed for the purpose of - developing Internet standards in which case the procedures for - copyrights defined in the Internet Standards process must be - followed, or as required to translate it into languages other than - English. - - The limited permissions granted above are perpetual and will not be - revoked by the Internet Society or its successors or assigns. - - This document and the information contained herein is provided on an - "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING - TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING - BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION - HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF - MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. - - - - - - - - - - - - - - - - - - - - - - - - -Myers Standards Track [Page 16] - diff --git a/doc/rfc/rfc2279.txt b/doc/rfc/rfc2279.txt deleted file mode 100644 index 3a3495cbe4..0000000000 --- a/doc/rfc/rfc2279.txt +++ /dev/null @@ -1,563 +0,0 @@ - - - - - - -Network Working Group F. Yergeau -Request for Comments: 2279 Alis Technologies -Obsoletes: 2044 January 1998 -Category: Standards Track - - - UTF-8, a transformation format of ISO 10646 - -Status of this Memo - - This document specifies an Internet standards track protocol for the - Internet community, and requests discussion and suggestions for - improvements. Please refer to the current edition of the "Internet - Official Protocol Standards" (STD 1) for the standardization state - and status of this protocol. Distribution of this memo is unlimited. - -Copyright Notice - - Copyright (C) The Internet Society (1998). All Rights Reserved. - -Abstract - - ISO/IEC 10646-1 defines a multi-octet character set called the - Universal Character Set (UCS) which encompasses most of the world's - writing systems. Multi-octet characters, however, are not compatible - with many current applications and protocols, and this has led to the - development of a few so-called UCS transformation formats (UTF), each - with different characteristics. UTF-8, the object of this memo, has - the characteristic of preserving the full US-ASCII range, providing - compatibility with file systems, parsers and other software that rely - on US-ASCII values but are transparent to other values. This memo - updates and replaces RFC 2044, in particular addressing the question - of versions of the relevant standards. - -1. Introduction - - ISO/IEC 10646-1 [ISO-10646] defines a multi-octet character set - called the Universal Character Set (UCS), which encompasses most of - the world's writing systems. Two multi-octet encodings are defined, - a four-octet per character encoding called UCS-4 and a two-octet per - character encoding called UCS-2, able to address only the first 64K - characters of the UCS (the Basic Multilingual Plane, BMP), outside of - which there are currently no assignments. - - It is noteworthy that the same set of characters is defined by the - Unicode standard [UNICODE], which further defines additional - character properties and other application details of great interest - to implementors, but does not have the UCS-4 encoding. Up to the - - - -Yergeau Standards Track [Page 1] - -RFC 2279 UTF-8 January 1998 - - - present time, changes in Unicode and amendments to ISO/IEC 10646 have - tracked each other, so that the character repertoires and code point - assignments have remained in sync. The relevant standardization - committees have committed to maintain this very useful synchronism. - - The UCS-2 and UCS-4 encodings, however, are hard to use in many - current applications and protocols that assume 8 or even 7 bit - characters. Even newer systems able to deal with 16 bit characters - cannot process UCS-4 data. This situation has led to the development - of so-called UCS transformation formats (UTF), each with different - characteristics. - - UTF-1 has only historical interest, having been removed from ISO/IEC - 10646. UTF-7 has the quality of encoding the full BMP repertoire - using only octets with the high-order bit clear (7 bit US-ASCII - values, [US-ASCII]), and is thus deemed a mail-safe encoding - ([RFC2152]). UTF-8, the object of this memo, uses all bits of an - octet, but has the quality of preserving the full US-ASCII range: - US-ASCII characters are encoded in one octet having the normal US- - ASCII value, and any octet with such a value can only stand for an - US-ASCII character, and nothing else. - - UTF-16 is a scheme for transforming a subset of the UCS-4 repertoire - into pairs of UCS-2 values from a reserved range. UTF-16 impacts - UTF-8 in that UCS-2 values from the reserved range must be treated - specially in the UTF-8 transformation. - - UTF-8 encodes UCS-2 or UCS-4 characters as a varying number of - octets, where the number of octets, and the value of each, depend on - the integer value assigned to the character in ISO/IEC 10646. This - transformation format has the following characteristics (all values - are in hexadecimal): - - - Character values from 0000 0000 to 0000 007F (US-ASCII repertoire) - correspond to octets 00 to 7F (7 bit US-ASCII values). A direct - consequence is that a plain ASCII string is also a valid UTF-8 - string. - - - US-ASCII values do not appear otherwise in a UTF-8 encoded - character stream. This provides compatibility with file systems - or other software (e.g. the printf() function in C libraries) that - parse based on US-ASCII values but are transparent to other - values. - - - Round-trip conversion is easy between UTF-8 and either of UCS-4, - UCS-2. - - - - - -Yergeau Standards Track [Page 2] - -RFC 2279 UTF-8 January 1998 - - - - The first octet of a multi-octet sequence indicates the number of - octets in the sequence. - - - The octet values FE and FF never appear. - - - Character boundaries are easily found from anywhere in an octet - stream. - - - The lexicographic sorting order of UCS-4 strings is preserved. Of - course this is of limited interest since the sort order is not - culturally valid in either case. - - - The Boyer-Moore fast search algorithm can be used with UTF-8 data. - - - UTF-8 strings can be fairly reliably recognized as such by a - simple algorithm, i.e. the probability that a string of characters - in any other encoding appears as valid UTF-8 is low, diminishing - with increasing string length. - - UTF-8 was originally a project of the X/Open Joint - Internationalization Group XOJIG with the objective to specify a File - System Safe UCS Transformation Format [FSS-UTF] that is compatible - with UNIX systems, supporting multilingual text in a single encoding. - The original authors were Gary Miller, Greger Leijonhufvud and John - Entenmann. Later, Ken Thompson and Rob Pike did significant work for - the formal UTF-8. - - A description can also be found in Unicode Technical Report #4 and in - the Unicode Standard, version 2.0 [UNICODE]. The definitive - reference, including provisions for UTF-16 data within UTF-8, is - Annex R of ISO/IEC 10646-1 [ISO-10646]. - -2. UTF-8 definition - - In UTF-8, characters are encoded using sequences of 1 to 6 octets. - The only octet of a "sequence" of one has the higher-order bit set to - 0, the remaining 7 bits being used to encode the character value. In - a sequence of n octets, n>1, the initial octet has the n higher-order - bits set to 1, followed by a bit set to 0. The remaining bit(s) of - that octet contain bits from the value of the character to be - encoded. The following octet(s) all have the higher-order bit set to - 1 and the following bit set to 0, leaving 6 bits in each to contain - bits from the character to be encoded. - - The table below summarizes the format of these different octet types. - The letter x indicates bits available for encoding bits of the UCS-4 - character value. - - - - -Yergeau Standards Track [Page 3] - -RFC 2279 UTF-8 January 1998 - - - UCS-4 range (hex.) UTF-8 octet sequence (binary) - 0000 0000-0000 007F 0xxxxxxx - 0000 0080-0000 07FF 110xxxxx 10xxxxxx - 0000 0800-0000 FFFF 1110xxxx 10xxxxxx 10xxxxxx - - 0001 0000-001F FFFF 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx - 0020 0000-03FF FFFF 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx - 0400 0000-7FFF FFFF 1111110x 10xxxxxx ... 10xxxxxx - - Encoding from UCS-4 to UTF-8 proceeds as follows: - - 1) Determine the number of octets required from the character value - and the first column of the table above. It is important to note - that the rows of the table are mutually exclusive, i.e. there is - only one valid way to encode a given UCS-4 character. - - 2) Prepare the high-order bits of the octets as per the second column - of the table. - - 3) Fill in the bits marked x from the bits of the character value, - starting from the lower-order bits of the character value and - putting them first in the last octet of the sequence, then the - next to last, etc. until all x bits are filled in. - - The algorithm for encoding UCS-2 (or Unicode) to UTF-8 can be - obtained from the above, in principle, by simply extending each - UCS-2 character with two zero-valued octets. However, pairs of - UCS-2 values between D800 and DFFF (surrogate pairs in Unicode - parlance), being actually UCS-4 characters transformed through - UTF-16, need special treatment: the UTF-16 transformation must be - undone, yielding a UCS-4 character that is then transformed as - above. - - Decoding from UTF-8 to UCS-4 proceeds as follows: - - 1) Initialize the 4 octets of the UCS-4 character with all bits set - to 0. - - 2) Determine which bits encode the character value from the number of - octets in the sequence and the second column of the table above - (the bits marked x). - - 3) Distribute the bits from the sequence to the UCS-4 character, - first the lower-order bits from the last octet of the sequence and - proceeding to the left until no x bits are left. - - If the UTF-8 sequence is no more than three octets long, decoding - can proceed directly to UCS-2. - - - -Yergeau Standards Track [Page 4] - -RFC 2279 UTF-8 January 1998 - - - NOTE -- actual implementations of the decoding algorithm above - should protect against decoding invalid sequences. For - instance, a naive implementation may (wrongly) decode the - invalid UTF-8 sequence C0 80 into the character U+0000, which - may have security consequences and/or cause other problems. See - the Security Considerations section below. - - A more detailed algorithm and formulae can be found in [FSS_UTF], - [UNICODE] or Annex R to [ISO-10646]. - -3. Versions of the standards - - ISO/IEC 10646 is updated from time to time by published amendments; - similarly, different versions of the Unicode standard exist: 1.0, 1.1 - and 2.0 as of this writing. Each new version obsoletes and replaces - the previous one, but implementations, and more significantly data, - are not updated instantly. - - In general, the changes amount to adding new characters, which does - not pose particular problems with old data. Amendment 5 to ISO/IEC - 10646, however, has moved and expanded the Korean Hangul block, - thereby making any previous data containing Hangul characters invalid - under the new version. Unicode 2.0 has the same difference from - Unicode 1.1. The official justification for allowing such an - incompatible change was that no implementations and no data - containing Hangul existed, a statement that is likely to be true but - remains unprovable. The incident has been dubbed the "Korean mess", - and the relevant committees have pledged to never, ever again make - such an incompatible change. - - New versions, and in particular any incompatible changes, have q - conseuences regarding MIME character encoding labels, to be discussed - in section 5. - -4. Examples - - The UCS-2 sequence "A." (0041, 2262, 0391, - 002E) may be encoded in UTF-8 as follows: - - 41 E2 89 A2 CE 91 2E - - The UCS-2 sequence representing the Hangul characters for the Korean - word "hangugo" (D55C, AD6D, C5B4) may be encoded as follows: - - ED 95 9C EA B5 AD EC 96 B4 - - - - - - -Yergeau Standards Track [Page 5] - -RFC 2279 UTF-8 January 1998 - - - The UCS-2 sequence representing the Han characters for the Japanese - word "nihongo" (65E5, 672C, 8A9E) may be encoded as follows: - - E6 97 A5 E6 9C AC E8 AA 9E - -5. MIME registration - - This memo is meant to serve as the basis for registration of a MIME - character set parameter (charset) [CHARSET-REG]. The proposed - charset parameter value is "UTF-8". This string labels media types - containing text consisting of characters from the repertoire of - ISO/IEC 10646 including all amendments at least up to amendment 5 - (Korean block), encoded to a sequence of octets using the encoding - scheme outlined above. UTF-8 is suitable for use in MIME content - types under the "text" top-level type. - - It is noteworthy that the label "UTF-8" does not contain a version - identification, referring generically to ISO/IEC 10646. This is - intentional, the rationale being as follows: - - A MIME charset label is designed to give just the information needed - to interpret a sequence of bytes received on the wire into a sequence - of characters, nothing more (see RFC 2045, section 2.2, in [MIME]). - As long as a character set standard does not change incompatibly, - version numbers serve no purpose, because one gains nothing by - learning from the tag that newly assigned characters may be received - that one doesn't know about. The tag itself doesn't teach anything - about the new characters, which are going to be received anyway. - - Hence, as long as the standards evolve compatibly, the apparent - advantage of having labels that identify the versions is only that, - apparent. But there is a disadvantage to such version-dependent - labels: when an older application receives data accompanied by a - newer, unknown label, it may fail to recognize the label and be - completely unable to deal with the data, whereas a generic, known - label would have triggered mostly correct processing of the data, - which may well not contain any new characters. - - Now the "Korean mess" (ISO/IEC 10646 amendment 5) is an incompatible - change, in principle contradicting the appropriateness of a version - independent MIME charset label as described above. But the - compatibility problem can only appear with data containing Korean - Hangul characters encoded according to Unicode 1.1 (or equivalently - ISO/IEC 10646 before amendment 5), and there is arguably no such data - to worry about, this being the very reason the incompatible change - was deemed acceptable. - - - - - -Yergeau Standards Track [Page 6] - -RFC 2279 UTF-8 January 1998 - - - In practice, then, a version-independent label is warranted, provided - the label is understood to refer to all versions after Amendment 5, - and provided no incompatible change actually occurs. Should - incompatible changes occur in a later version of ISO/IEC 10646, the - MIME charset label defined here will stay aligned with the previous - version until and unless the IETF specifically decides otherwise. - - It is also proposed to register the charset parameter value - "UNICODE-1-1-UTF-8", for the exclusive purpose of labelling text data - containing Hangul syllables encoded to UTF-8 without taking into - account Amendment 5 of ISO/IEC 10646 (i.e. using the pre-amendment 5 - code point assignments). Any other UTF-8 data SHOULD NOT use this - label, in particular data not containing any Hangul syllables, and it - is felt important to strongly recommend against creating any new - Hangul-containing data without taking Amendment 5 of ISO/IEC 10646 - into account. - -6. Security Considerations - - Implementors of UTF-8 need to consider the security aspects of how - they handle illegal UTF-8 sequences. It is conceivable that in some - circumstances an attacker would be able to exploit an incautious - UTF-8 parser by sending it an octet sequence that is not permitted by - the UTF-8 syntax. - - A particularly subtle form of this attack could be carried out - against a parser which performs security-critical validity checks - against the UTF-8 encoded form of its input, but interprets certain - illegal octet sequences as characters. For example, a parser might - prohibit the NUL character when encoded as the single-octet sequence - 00, but allow the illegal two-octet sequence C0 80 and interpret it - as a NUL character. Another example might be a parser which - prohibits the octet sequence 2F 2E 2E 2F ("/../"), yet permits the - illegal octet sequence 2F C0 AE 2E 2F. - -Acknowledgments - - The following have participated in the drafting and discussion of - this memo: - - James E. Agenbroad Andries Brouwer - Martin J. D|rst Ned Freed - David Goldsmith Edwin F. Hart - Kent Karlsson Markus Kuhn - Michael Kung Alain LaBonte - John Gardiner Myers Murray Sargent - Keld Simonsen Arnold Winkler - - - - -Yergeau Standards Track [Page 7] - -RFC 2279 UTF-8 January 1998 - - -Bibliography - - [CHARSET-REG] Freed, N., and J. Postel, "IANA Charset Registration - Procedures", BCP 19, RFC 2278, January 1998. - - [FSS_UTF] X/Open CAE Specification C501 ISBN 1-85912-082-2 28cm. - 22p. pbk. 172g. 4/95, X/Open Company Ltd., "File - System Safe UCS Transformation Format (FSS_UTF)", - X/Open Preleminary Specification, Document Number - P316. Also published in Unicode Technical Report #4. - - [ISO-10646] ISO/IEC 10646-1:1993. International Standard -- - Information technology -- Universal Multiple-Octet - Coded Character Set (UCS) -- Part 1: Architecture and - Basic Multilingual Plane. Five amendments and a - technical corrigendum have been published up to now. - UTF-8 is described in Annex R, published as Amendment - 2. UTF-16 is described in Annex Q, published as - Amendment 1. 17 other amendments are currently at - various stages of standardization. - - [MIME] Freed, N., and N. Borenstein, "Multipurpose Internet - Mail Extensions (MIME) Part One: Format of Internet - Message Bodies", RFC 2045. N. Freed, N. Borenstein, - "Multipurpose Internet Mail Extensions (MIME) Part - Two: Media Types", RFC 2046. K. Moore, "MIME - (Multipurpose Internet Mail Extensions) Part Three: - Message Header Extensions for Non-ASCII Text", RFC - 2047. N. Freed, J. Klensin, J. Postel, "Multipurpose - Internet Mail Extensions (MIME) Part Four: - Registration Procedures", RFC 2048. N. Freed, N. - Borenstein, " Multipurpose Internet Mail Extensions - (MIME) Part Five: Conformance Criteria and Examples", - RFC 2049. All November 1996. - - [RFC2152] Goldsmith, D., and M. Davis, "UTF-7: A Mail-safe - Transformation Format of Unicode", RFC 1642, Taligent - inc., May 1997. (Obsoletes RFC1642) - - [UNICODE] The Unicode Consortium, "The Unicode Standard -- - Version 2.0", Addison-Wesley, 1996. - - [US-ASCII] Coded Character Set--7-bit American Standard Code for - Information Interchange, ANSI X3.4-1986. - - - - - - - -Yergeau Standards Track [Page 8] - -RFC 2279 UTF-8 January 1998 - - -Author's Address - - Francois Yergeau - Alis Technologies - 100, boul. Alexis-Nihon - Suite 600 - Montreal QC H4M 2P2 - Canada - - Phone: +1 (514) 747-2547 - Fax: +1 (514) 747-2561 - EMail: fyergeau@alis.com - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Yergeau Standards Track [Page 9] - -RFC 2279 UTF-8 January 1998 - - -Full Copyright Statement - - Copyright (C) The Internet Society (1998). All Rights Reserved. - - This document and translations of it may be copied and furnished to - others, and derivative works that comment on or otherwise explain it - or assist in its implementation may be prepared, copied, published - and distributed, in whole or in part, without restriction of any - kind, provided that the above copyright notice and this paragraph are - included on all such copies and derivative works. However, this - document itself may not be modified in any way, such as by removing - the copyright notice or references to the Internet Society or other - Internet organizations, except as needed for the purpose of - developing Internet standards in which case the procedures for - copyrights defined in the Internet Standards process must be - followed, or as required to translate it into languages other than - English. - - The limited permissions granted above are perpetual and will not be - revoked by the Internet Society or its successors or assigns. - - This document and the information contained herein is provided on an - "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING - TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING - BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION - HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF - MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. - - - - - - - - - - - - - - - - - - - - - - - - -Yergeau Standards Track [Page 10] - diff --git a/doc/rfc/rfc2828.txt b/doc/rfc/rfc2828.txt deleted file mode 100644 index 47e819c698..0000000000 --- a/doc/rfc/rfc2828.txt +++ /dev/null @@ -1,11875 +0,0 @@ - - - - - - -Network Working Group R. Shirey -Request for Comments: 2828 GTE / BBN Technologies -FYI: 36 May 2000 -Category: Informational - - - Internet Security Glossary - -Status of this Memo - - This memo provides information for the Internet community. It does - not specify an Internet standard of any kind. Distribution of this - memo is unlimited. - -Copyright Notice - - Copyright (C) The Internet Society (2000). All Rights Reserved. - -Abstract - - This Glossary (191 pages of definitions and 13 pages of references) - provides abbreviations, explanations, and recommendations for use of - information system security terminology. The intent is to improve the - comprehensibility of writing that deals with Internet security, - particularly Internet Standards documents (ISDs). To avoid confusion, - ISDs should use the same term or definition whenever the same concept - is mentioned. To improve international understanding, ISDs should use - terms in their plainest, dictionary sense. ISDs should use terms - established in standards documents and other well-founded - publications and should avoid substituting private or newly made-up - terms. ISDs should avoid terms that are proprietary or otherwise - favor a particular vendor, or that create a bias toward a particular - security technology or mechanism versus other, competing techniques - that already exist or might be developed in the future. - - - - - - - - - - - - - - - - - -Shirey Informational [Page 1] - -RFC 2828 Internet Security Glossary May 2000 - - -Table of Contents - - 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 2. Explanation of Paragraph Markings . . . . . . . . . . . . . . 4 - 2.1 Recommended Terms with an Internet Basis ("I") . . . . . . 4 - 2.2 Recommended Terms with a Non-Internet Basis ("N") . . . . 5 - 2.3 Other Definitions ("O") . . . . . . . . . . . . . . . . . 5 - 2.4 Deprecated Terms, Definitions, and Uses ("D") . . . . . . 6 - 2.5 Commentary and Additional Guidance ("C") . . . . . . . . . 6 - 3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 6 - 4. References . . . . . . . . . . . . . . . . . . . . . . . . . . 197 - 5. Security Considerations . . . . . . . . . . . . . . . . . . . 211 - 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 211 - 7. Author's Address . . . . . . . . . . . . . . . . . . . . . . . 211 - 8. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 212 - -1. Introduction - - This Glossary provides an internally consistent, complementary set of - abbreviations, definitions, explanations, and recommendations for use - of terminology related to information system security. The intent of - this Glossary is to improve the comprehensibility of Internet - Standards documents (ISDs)--i.e., RFCs, Internet-Drafts, and other - material produced as part of the Internet Standards Process [R2026]-- - and of all other Internet material, too. Some non-security terms are - included to make the Glossary self-contained, but more complete lists - of networking terms are available elsewhere [R1208, R1983]. - - Some glossaries (e.g., [Raym]) list terms that are not listed here - but could be applied to Internet security. However, those terms have - not been included in this Glossary because they are not appropriate - for ISDs. - - This Glossary marks terms and definitions as being either endorsed or - deprecated for use in ISDs, but this Glossary is not an Internet - standard. The key words "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", - and "OPTIONAL" are intended to be interpreted the same way as in an - Internet Standard [R2119], but this guidance represents only the - recommendations of this author. However, this Glossary includes - reasons for the recommendations--particularly for the SHOULD NOTs--so - that readers can judge for themselves whether to follow the - recommendations. - - - - - - - - - -Shirey Informational [Page 2] - -RFC 2828 Internet Security Glossary May 2000 - - - This Glossary supports the goals of the Internet Standards Process: - - o Clear, Concise, and Easily Understood Documentation - - This Glossary seeks to improve comprehensibility of security- - related content of ISDs. That requires wording to be clear and - understandable, and requires the set of security-related terms and - definitions to be consistent and self-supporting. Also, the - terminology needs to be uniform across all ISDs; i.e., the same - term or definition needs to be used whenever and wherever the same - concept is mentioned. Harmonization of existing ISDs need not be - done immediately, but it is desirable to correct and standardize - the terminology when new versions are issued in the normal course - of standards development and evolution. - - o Technical Excellence - - Just as Internet Standard (STD) protocols should operate - effectively, ISDs should use terminology accurately, precisely, - and unambiguously to enable Internet Standards to be implemented - correctly. - - o Prior Implementation and Testing - - Just as STD protocols require demonstrated experience and - stability before adoption, ISDs need to use well-established - language. Using terms in their plainest, dictionary sense (when - appropriate) helps to ensure international understanding. ISDs - need to avoid using private, made-up terms in place of generally- - accepted terms from standards and other publications. ISDs need to - avoid substituting new definitions that conflict with established - ones. ISDs need to avoid using "cute" synonyms (e.g., see: Green - Book); no matter how popular a nickname may be in one community, - it is likely to cause confusion in another. - - o Openness, Fairness, and Timeliness - - ISDs need to avoid terms that are proprietary or otherwise favor a - particular vendor, or that create a bias toward a particular - security technology or mechanism over other, competing techniques - that already exist or might be developed in the future. The set of - terminology used across the set of ISDs needs to be flexible and - adaptable as the state of Internet security art evolves. - - - - - - - - -Shirey Informational [Page 3] - -RFC 2828 Internet Security Glossary May 2000 - - -2. Explanation of Paragraph Markings - - Section 3 marks terms and definitions as follows: - - o Capitalization: Only terms that are proper nouns are capitalized. - - o Paragraph Marking: Definitions and explanations are stated in - paragraphs that are marked as follows: - - - "I" identifies a RECOMMENDED Internet definition. - - "N" identifies a RECOMMENDED non-Internet definition. - - "O" identifies a definition that is not recommended as the first - choice for Internet documents but is something that authors of - Internet documents need to know. - - "D" identifies a term or definition that SHOULD NOT be used in - Internet documents. - - "C" identifies commentary or additional usage guidance. - - The rest of Section 2 further explains these five markings. - -2.1 Recommended Terms with an Internet Basis ("I") - - The paragraph marking "I" (as opposed to "O") indicates a definition - that SHOULD be the first choice for use in ISDs. Most terms and - definitions of this type MAY be used in ISDs; however, some "I" - definitions are accompanied by a "D" paragraph that recommends - against using the term. Also, some "I" definitions are preceded by an - indication of a contextual usage limitation (e.g., see: - certification), and ISDs should not the term and definition outside - that context - - An "I" (as opposed to an "N") also indicates that the definition has - an Internet basis. That is, either the Internet Standards Process is - authoritative for the term, or the term is sufficiently generic that - this Glossary can freely state a definition without contradicting a - non-Internet authority (e.g., see: attack). - - Many terms with "I" definitions are proper nouns (e.g., see: - Internet Protocol). For such terms, the "I" definition is intended - only to provide basic information; the authoritative definition is - found elsewhere. - - For a proper noun identified as an "Internet protocol", please refer - to the current edition of "Internet Official Protocol Standards" (STD - 1) for the standardization state and status of the protocol. - - - - - - -Shirey Informational [Page 4] - -RFC 2828 Internet Security Glossary May 2000 - - -2.2 Recommended Terms with a Non-Internet Basis ("N") - - The paragraph marking "N" (as opposed to "O") indicates a definition - that SHOULD be the first choice for the term, if the term is used at - all in Internet documents. Terms and definitions of this type MAY be - used in Internet documents (e.g., see: X.509 public-key certificate). - - However, an "N" (as opposed to an "I") also indicates a definition - that has a non-Internet basis or origin. Many such definitions are - preceded by an indication of a contextual usage limitation, and this - Glossary's endorsement does not apply outside that context. Also, - some contexts are rarely if ever expected to occur in a Internet - document (e.g., see: baggage). In those cases, the listing exists to - make Internet authors aware of the non-Internet usage so that they - can avoid conflicts with non-Internet documents. - - Many terms with "N" definitions are proper nouns (e.g., see: - Computer Security Objects Register). For such terms, the "N" - definition is intended only to provide basic information; the - authoritative definition is found elsewhere. - -2.3 Other Definitions ("O") - - The paragraph marking "O" indicates a definition that has a non- - Internet basis, but indicates that the definition SHOULD NOT be used - in ISDs *except* in cases where the term is specifically identified - as non-Internet. - - For example, an ISD might mention "BCA" (see: brand certification - authority) or "baggage" as an example to illustrate some concept; in - that case, the document should specifically say "SET(trademark) BCA" - or "SET(trademark) baggage" and include the definition of the term. - - For some terms that have a definition published by a non-Internet - authority--government (see: object reuse), industry (see: Secure Data - Exchange), national (see: Data Encryption Standard), or international - (see: data confidentiality)--this Glossary marks the definition "N", - recommending its use in Internet documents. In other cases, the non- - Internet definition of a term is inadequate or inappropriate for - ISDs. For example, it may be narrow or outdated, or it may need - clarification by substituting more careful or more explanatory - wording using other terms that are defined in this Glossary. In those - cases, this Glossary marks the tern "O" and provides an "I" - definition (or sometimes a different "N" definition), which precedes - and supersedes the definition marked "O". - - - - - - -Shirey Informational [Page 5] - -RFC 2828 Internet Security Glossary May 2000 - - - In most of the cases where this Glossary provides a definition to - supersede one from a non-Internet standard, the substitute is - intended to subsume the meaning of the superseded "O" definition and - not conflict with it. For the term "security service", for example, - the "O" definition deals narrowly with only communication services - provided by layers in the OSI model and is inadequate for the full - range of ISD usage; the "I" definition can be used in more situations - and for more kinds of service. However, the "O" definition is also - provided here so that ISD authors will be aware of the context in - which the term is used more narrowly. - - When making substitutions, this Glossary attempts to use - understandable English that does not contradict any non-Internet - authority. Still, terminology differs between the standards of the - American Bar Association, OSI, SET, the U.S. Department of Defense, - and other authorities, and this Glossary probably is not exactly - aligned with all of them. - -2.4 Deprecated Terms, Definitions, and Uses ("D") - - If this Glossary recommends that a term or definition SHOULD NOT be - used in ISDs, then either the definition has the paragraph marking - "D", or the restriction is stated in a "D" paragraph that immediately - follows the term or definition. - -2.5 Commentary and Additional Guidance ("C") - - The paragraph marking "C" identifies text that is advisory or - tutorial. This text MAY be reused in other Internet documents. This - text is not intended to be authoritative, but is provided to clarify - the definitions and to enhance this Glossary so that Internet - security novices can use it as a tutorial. - -3. Definitions - - Note: Each acronym or other abbreviation (except items of common - English usage, such as "e.g.", "etc.", "i.e.", "vol.", "pp.", "U.S.") - that is used in this Glossary, either in a definition or as a subpart - of a defined term, is also defined in this Glossary. - - $ 3DES - See: triple DES. - - $ *-property - (N) (Pronounced "star property".) See: "confinement property" - under Bell-LaPadula Model. - - - - - -Shirey Informational [Page 6] - -RFC 2828 Internet Security Glossary May 2000 - - - $ ABA Guidelines - (N) "American Bar Association (ABA) Digital Signature Guidelines" - [ABA], a framework of legal principles for using digital - signatures and digital certificates in electronic commerce. - - $ Abstract Syntax Notation One (ASN.1) - (N) A standard for describing data objects. [X680] - - (C) OSI standards use ASN.1 to specify data formats for protocols. - OSI defines functionality in layers. Information objects at higher - layers are abstractly defined to be implemented with objects at - lower layers. A higher layer may define transfers of abstract - objects between computers, and a lower layer may define transfers - concretely as strings of bits. Syntax is needed to define abstract - objects, and encoding rules are needed to transform between - abstract objects and bit strings. (See: Basic Encoding Rules.) - - (C) In ASN.1, formal names are written without spaces, and - separate words in a name are indicated by capitalizing the first - letter of each word except the first word. For example, the name - of a CRL is "certificateRevocationList". - - $ ACC - See: access control center. - - $ access - (I) The ability and means to communicate with or otherwise - interact with a system in order to use system resources to either - handle information or gain knowledge of the information the system - contains. - - (O) "A specific type of interaction between a subject and an - object that results in the flow of information from one to the - other." [NCS04] - - (C) In this Glossary, "access" is intended to cover any ability to - communicate with a system, including one-way communication in - either direction. In actual practice, however, entities outside a - security perimeter that can receive output from the system but - cannot provide input or otherwise directly interact with the - system, might be treated as not having "access" and, therefore, be - exempt from security policy requirements, such as the need for a - security clearance. - - $ access control - (I) Protection of system resources against unauthorized access; a - process by which use of system resources is regulated according to - a security policy and is permitted by only authorized entities - - - -Shirey Informational [Page 7] - -RFC 2828 Internet Security Glossary May 2000 - - - (users, programs, processes, or other systems) according to that - policy. (See: access, access control service.) - - (O) "The prevention of unauthorized use of a resource, including - the prevention of use of a resource in an unauthorized manner." - [I7498 Part 2] - - $ access control center (ACC) - (I) A computer containing a database with entries that define a - security policy for an access control service. - - (C) An ACC is sometimes used in conjunction with a key center to - implement access control in a key distribution system for - symmetric cryptography. - - $ access control list (ACL) - (I) A mechanism that implements access control for a system - resource by enumerating the identities of the system entities that - are permitted to access the resource. (See: capability.) - - $ access control service - (I) A security service that protects against a system entity using - a system resource in a way not authorized by the system's security - policy; in short, protection of system resources against - unauthorized access. (See: access control, discretionary access - control, identity-based security policy, mandatory access control, - rule-based security policy.) - - (C) This service includes protecting against use of a resource in - an unauthorized manner by an entity that is authorized to use the - resource in some other manner. The two basic mechanisms for - implementing this service are ACLs and tickets. - - $ access mode - (I) A distinct type of data processing operation--e.g., read, - write, append, or execute--that a subject can potentially perform - on an object in a computer system. - - $ accountability - (I) The property of a system (including all of its system - resources) that ensures that the actions of a system entity may be - traced uniquely to that entity, which can be held responsible for - its actions. (See: audit service.) - - (C) Accountability permits detection and subsequent investigation - of security breaches. - - - - - -Shirey Informational [Page 8] - -RFC 2828 Internet Security Glossary May 2000 - - - $ accredit - $ accreditation - (I) An administrative declaration by a designated authority that - an information system is approved to operate in a particular - security configuration with a prescribed set of safeguards. - [FP102] (See: certification.) - - (C) An accreditation is usually based on a technical certification - of the system's security mechanisms. The terms "certification" and - "accreditation" are used more in the U.S. Department of Defense - and other government agencies than in commercial organizations. - However, the concepts apply any place where managers are required - to deal with and accept responsibility for security risks. The - American Bar Association is developing accreditation criteria for - CAs. - - $ ACL - See: access control list. - - $ acquirer - (N) SET usage: "The financial institution that establishes an - account with a merchant and processes payment card authorizations - and payments." [SET1] - - (O) "The institution (or its agent) that acquires from the card - acceptor the financial data relating to the transaction and - initiates that data into an interchange system." [SET2] - - $ active attack - See: (secondary definition under) attack. - - $ active wiretapping - See: (secondary definition under) wiretapping. - - $ add-on security - (I) "The retrofitting of protection mechanisms, implemented by - hardware or software, after the [automatic data processing] system - has become operational." [FP039] - - $ administrative security - (I) Management procedures and constraints to prevent unauthorized - access to a system. (See: security architecture.) - - (O) "The management constraints, operational procedures, - accountability procedures, and supplemental controls established - to provide an acceptable level of protection for sensitive data." - [FP039] - - - - -Shirey Informational [Page 9] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) Examples include clear delineation and separation of duties, - and configuration control. - - $ Advanced Encryption Standard (AES) - (N) A future FIPS publication being developed by NIST to succeed - DES. Intended to specify an unclassified, publicly-disclosed, - symmetric encryption algorithm, available royalty-free worldwide. - - $ adversary - (I) An entity that attacks, or is a threat to, a system. - - $ aggregation - (I) A circumstance in which a collection of information items is - required to be classified at a higher security level than any of - the individual items that comprise it. - - $ AH - See: Authentication Header - - $ algorithm - (I) A finite set of step-by-step instructions for a problem- - solving or computation procedure, especially one that can be - implemented by a computer. (See: cryptographic algorithm.) - - $ alias - (I) A name that an entity uses in place of its real name, usually - for the purpose of either anonymity or deception. - - $ American National Standards Institute (ANSI) - (N) A private, not-for-profit association of users, manufacturers, - and other organizations, that administers U.S. private sector - voluntary standards. - - (C) ANSI is the sole U.S. representative to the two major non- - treaty international standards organizations, ISO and, via the - U.S. National Committee (USNC), the International Electrotechnical - Commission (IEC). - - $ anonymous - (I) The condition of having a name that is unknown or concealed. - (See: anonymous login.) - - (C) An application may require security services that maintain - anonymity of users or other system entities, perhaps to preserve - their privacy or hide them from attack. To hide an entity's real - name, an alias may be used. For example, a financial institution - may assign an account number. Parties to a transaction can thus - remain relatively anonymous, but can also accept the transaction - - - -Shirey Informational [Page 10] - -RFC 2828 Internet Security Glossary May 2000 - - - as legitimate. Real names of the parties cannot be easily - determined by observers of the transaction, but an authorized - third party may be able to map an alias to a real name, such as by - presenting the institution with a court order. In other - applications, anonymous entities may be completely untraceable. - - $ anonymous login - (I) An access control feature (or, rather, an access control - weakness) in many Internet hosts that enables users to gain access - to general-purpose or public services and resources on a host - (such as allowing any user to transfer data using File Transfer - Protocol) without having a pre-established, user-specific account - (i.e., user name and secret password). - - (C) This feature exposes a system to more threats than when all - the users are known, pre-registered entities that are individually - accountable for their actions. A user logs in using a special, - publicly known user name (e.g., "anonymous", "guest", or "ftp"). - To use the public login name, the user is not required to know a - secret password and may not be required to input anything at all - except the name. In other cases, to complete the normal sequence - of steps in a login protocol, the system may require the user to - input a matching, publicly known password (such as "anonymous") or - may ask the user for an e-mail address or some other arbitrary - character string. - - $ APOP - See: POP3 APOP. - - $ archive - (I) (1.) Noun: A collection of data that is stored for a - relatively long period of time for historical and other purposes, - such as to support audit service, availability service, or system - integrity service. (See: backup.) (2.) Verb: To store data in such - a way. (See: back up.) - - (C) A digital signature may need to be verified many years after - the signing occurs. The CA--the one that issued the certificate - containing the public key needed to verify that signature--may not - stay in operation that long. So every CA needs to provide for - long-term storage of the information needed to verify the - signatures of those to whom it issues certificates. - - $ ARPANET - (N) Advanced Research Projects Agency Network, a pioneer packet- - switched network that was built in the early 1970s under contract - to the U.S. Government, led to the development of today's - Internet, and was decommissioned in June 1990. - - - -Shirey Informational [Page 11] - -RFC 2828 Internet Security Glossary May 2000 - - - $ ASN.1 - See: Abstract Syntax Notation One. - - $ association - (I) A cooperative relationship between system entities, usually - for the purpose of transferring information between them. (See: - security association.) - - $ assurance - (I) (1.) An attribute of an information system that provides - grounds for having confidence that the system operates such that - the system security policy is enforced. (2.) A procedure that - ensures a system is developed and operated as intended by the - system's security policy. - - $ assurance level - (I) Evaluation usage: A specific level on a hierarchical scale - representing successively increased confidence that a target of - evaluation adequately fulfills the requirements. (E.g., see: - TCSEC.) - - $ asymmetric cryptography - (I) A modern branch of cryptography (popularly known as "public- - key cryptography") in which the algorithms employ a pair of keys - (a public key and a private key) and use a different component of - the pair for different steps of the algorithm. (See: key pair.) - - (C) Asymmetric algorithms have key management advantages over - equivalently strong symmetric ones. First, one key of the pair - does not need to be known by anyone but its owner; so it can more - easily be kept secret. Second, although the other key of the pair - is shared by all entities that use the algorithm, that key does - not need to be kept secret from other, non-using entities; so the - key distribution part of key management can be done more easily. - - (C) For encryption: In an asymmetric encryption algorithm (e.g., - see: RSA), when Alice wants to ensure confidentiality for data she - sends to Bob, she encrypts the data with a public key provided by - Bob. Only Bob has the matching private key that is needed to - decrypt the data. - - (C) For signature: In an asymmetric digital signature algorithm - (e.g., see: DSA), when Alice wants to ensure data integrity or - provide authentication for data she sends to Bob, she uses her - private key to sign the data (i.e., create a digital signature - based on the data). To verify the signature, Bob uses the matching - public key that Alice has provided. - - - - -Shirey Informational [Page 12] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) For key agreement: In an asymmetric key agreement algorithm - (e.g., see: Diffie-Hellman), Alice and Bob each send their own - public key to the other person. Then each uses their own private - key and the other's public key to compute the new key value. - - $ attack - (I) An assault on system security that derives from an intelligent - threat, i.e., an intelligent act that is a deliberate attempt - (especially in the sense of a method or technique) to evade - security services and violate the security policy of a system. - (See: penetration, violation, vulnerability.) - - - Active vs. passive: An "active attack" attempts to alter system - resources or affect their operation. A "passive attack" - attempts to learn or make use of information from the system - but does not affect system resources. (E.g., see: wiretapping.) - - - Insider vs. outsider: An "inside attack" is an attack initiated - by an entity inside the security perimeter (an "insider"), - i.e., an entity that is authorized to access system resources - but uses them in a way not approved by those who granted the - authorization. An "outside attack" is initiated from outside - the perimeter, by an unauthorized or illegitimate user of the - system (an "outsider"). In the Internet, potential outside - attackers range from amateur pranksters to organized criminals, - international terrorists, and hostile governments. - - (C) The term "attack" relates to some other basic security terms - as shown in the following diagram: - - + - - - - - - - - - - - - + + - - - - + + - - - - - - - - - - -+ - | An Attack: | |Counter- | | A System Resource: | - | i.e., A Threat Action | | measure | | Target of the Attack | - | +----------+ | | | | +-----------------+ | - | | Attacker |<==================||<========= | | - | | i.e., | Passive | | | | | Vulnerability | | - | | A Threat |<=================>||<========> | | - | | Agent | or Active | | | | +-------|||-------+ | - | +----------+ Attack | | | | VVV | - | | | | | Threat Consequences | - + - - - - - - - - - - - - + + - - - - + + - - - - - - - - - - -+ - - $ attribute authority - (I) A CA that issues attribute certificates. - - (O) "An authority, trusted by the verifier to delegate privilege, - which issues attribute certificates." [FPDAM] - - - - -Shirey Informational [Page 13] - -RFC 2828 Internet Security Glossary May 2000 - - - $ attribute certificate - (I) A digital certificate that binds a set of descriptive data - items, other than a public key, either directly to a subject name - or to the identifier of another certificate that is a public-key - certificate. [X509] - - (O) "A set of attributes of a user together with some other - information, rendered unforgeable by the digital signature created - using the private key of the CA which issued it." [X509] - - (O) "A data structure that includes some attribute values and - identification information about the owner of the attribute - certificate, all digitally signed by an Attribute Authority. This - authority's signature serves as the guarantee of the binding - between the attributes and their owner." [FPDAM] - - (C) A public-key certificate binds a subject name to a public key - value, along with information needed to perform certain - cryptographic functions. Other attributes of a subject, such as a - security clearance, may be certified in a separate kind of digital - certificate, called an attribute certificate. A subject may have - multiple attribute certificates associated with its name or with - each of its public-key certificates. - - (C) An attribute certificate might be issued to a subject in the - following situations: - - - Different lifetimes: When the lifetime of an attribute binding - is shorter than that of the related public-key certificate, or - when it is desirable not to need to revoke a subject's public - key just to revoke an attribute. - - - Different authorities: When the authority responsible for the - attributes is different than the one that issues the public-key - certificate for the subject. (There is no requirement that an - attribute certificate be issued by the same CA that issued the - associated public-key certificate.) - - $ audit service - (I) A security service that records information needed to - establish accountability for system events and for the actions of - system entities that cause them. (See: security audit.) - - $ audit trail - See: security audit trail. - - - - - - -Shirey Informational [Page 14] - -RFC 2828 Internet Security Glossary May 2000 - - - $ AUTH - See: POP3 AUTH. - - $ authentic signature - (I) A signature (particularly a digital signature) that can be - trusted because it can be verified. (See: validate vs. verify.) - - $ authenticate - (I) Verify (i.e., establish the truth of) an identity claimed by - or for a system entity. (See: authentication.) - - (D) In general English usage, this term usually means "to prove - genuine" (e.g., an art expert authenticates a Michelangelo - painting). But the recommended definition carries a much narrower - meaning. For example, to be precise, an ISD SHOULD NOT say "the - host authenticates each received datagram". Instead, the ISD - SHOULD say "the host authenticates the origin of each received - datagram". In most cases, we also can say "and verifies the - datagram's integrity", because that is usually implied. (See: - ("relationship between data integrity service and authentication - services" under) data integrity service.) - - (D) ISDs SHOULD NOT talk about authenticating a digital signature - or digital certificate. Instead, we "sign" and then "verify" - digital signatures, and we "issue" and then "validate" digital - certificates. (See: validate vs. verify.) - - $ authentication - (I) The process of verifying an identity claimed by or for a - system entity. (See: authenticate, authentication exchange, - authentication information, credential, data origin - authentication, peer entity authentication.) - - (C) An authentication process consists of two steps: - - 1. Identification step: Presenting an identifier to the security - system. (Identifiers should be assigned carefully, because - authenticated identities are the basis for other security - services, such as access control service.) - - 2. Verification step: Presenting or generating authentication - information that corroborates the binding between the entity - and the identifier. (See: verification.) - - (C) See: ("relationship between data integrity service and - authentication services" under) data integrity service. - - - - - -Shirey Informational [Page 15] - -RFC 2828 Internet Security Glossary May 2000 - - - $ authentication code - (D) ISDs SHOULD NOT use this term as a synonym for any form of - checksum, whether cryptographic or not. The word "authentication" - is misleading because the mechanism involved usually serves a data - integrity function rather than an authentication function, and the - word "code" is misleading because it implies that either encoding - or encryption is involved or that the term refers to computer - software. (See: message authentication code.) - - $ authentication exchange - (I) A mechanism to verify the identity of an entity by means of - information exchange. - - (O) "A mechanism intended to ensure the identity of an entity by - means of information exchange." [I7498 Part 2] - - $ Authentication Header (AH) - (I) An Internet IPsec protocol [R2402] designed to provide - connectionless data integrity service and data origin - authentication service for IP datagrams, and (optionally) to - provide protection against replay attacks. - - (C) Replay protection may be selected by the receiver when a - security association is established. AH authenticates upper-layer - protocol data units and as much of the IP header as possible. - However, some IP header fields may change in transit, and the - value of these fields, when the packet arrives at the receiver, - may not be predictable by the sender. Thus, the values of such - fields cannot be protected end-to-end by AH; protection of the IP - header by AH is only partial when such fields are present. - - (C) AH may be used alone, or in combination with the IPsec ESP - protocol, or in a nested fashion with tunneling. Security services - can be provided between a pair of communicating hosts, between a - pair of communicating security gateways, or between a host and a - gateway. ESP can provide the same security services as AH, and ESP - can also provide data confidentiality service. The main difference - between authentication services provided by ESP and AH is the - extent of the coverage; ESP does not protect IP header fields - unless they are encapsulated by AH. - - $ authentication information - (I) Information used to verify an identity claimed by or for an - entity. (See: authentication, credential.) - - (C) Authentication information may exist as, or be derived from, - one of the following: - - - - -Shirey Informational [Page 16] - -RFC 2828 Internet Security Glossary May 2000 - - - - Something the entity knows. (See: password). - - Something the entity possesses. (See: token.) - - Something the entity is. (See: biometric authentication.) - - $ authentication service - (I) A security service that verifies an identity claimed by or for - an entity. (See: authentication.) - - (C) In a network, there are two general forms of authentication - service: data origin authentication service and peer entity - authentication service. - - $ authenticity - (I) The property of being genuine and able to be verified and be - trusted. (See: authenticate, authentication, validate vs. verify) - - $ authority - (D) "An entity, responsible for the issuance of certificates." - [FPDAM] - - (C) ISDs SHOULD NOT use this term as a synonym for AA, CA, RA, - ORA, or similar terms, because it may cause confusion. Instead, - use the full term at the first instance of usage and then, if it - is necessary to shorten text, use the style of abbreviation - defined in this Glossary. - - (C) ISDs SHOULD NOT use this definition for any PKI entity, - because the definition is ambiguous with regard to whether the - entity actually issues certificates (e.g., attribute authority or - certification authority) or just has accountability for processes - that precede or follow signing (e.g., registration authority). - (See: issue.) - - $ authority certificate - (D) "A certificate issued to an authority (e.g. either to a - certification authority or to an attribute authority)." [FPDAM] - (See: authority.) - - (C) ISDs SHOULD NOT use this term or definition because they are - ambiguous with regard to which specific types of PKI entities they - address. - - $ authority revocation list (ARL) - (I) A data structure that enumerates digital certificates that - were issued to CAs but have been invalidated by their issuer prior - to when they were scheduled to expire. (See: certificate - expiration, X.509 authority revocation list.) - - - - -Shirey Informational [Page 17] - -RFC 2828 Internet Security Glossary May 2000 - - - (O) "A revocation list containing a list of public-key - certificates issued to authorities, which are no longer considered - valid by the certificate issuer." [FPDAM] - - $ authorization - $ authorize - (I) (1.) An "authorization" is a right or a permission that is - granted to a system entity to access a system resource. (2.) An - "authorization process" is a procedure for granting such rights. - (3.) To "authorize" means to grant such a right or permission. - (See: privilege.) - - (O) SET usage: "The process by which a properly appointed person - or persons grants permission to perform some action on behalf of - an organization. This process assesses transaction risk, confirms - that a given transaction does not raise the account holder's debt - above the account's credit limit, and reserves the specified - amount of credit. (When a merchant obtains authorization, payment - for the authorized amount is guaranteed--provided, of course, that - the merchant followed the rules associated with the authorization - process.)" [SET2] - - $ automated information system - (I) An organized assembly of resources and procedures--i.e., - computing and communications equipment and services, with their - supporting facilities and personnel--that collect, record, - process, store, transport, retrieve, or display information to - accomplish a specified set of functions. - - $ availability - (I) The property of a system or a system resource being accessible - and usable upon demand by an authorized system entity, according - to performance specifications for the system; i.e., a system is - available if it provides services according to the system design - whenever users request them. (See: critical, denial of service, - reliability, survivability.) - - (O) "The property of being accessible and usable upon demand by an - authorized entity." [I7498 Part 2] - - $ availability service - (I) A security service that protects a system to ensure its - availability. - - (C) This service addresses the security concerns raised by denial- - of-service attacks. It depends on proper management and control of - system resources, and thus depends on access control service and - other security services. - - - -Shirey Informational [Page 18] - -RFC 2828 Internet Security Glossary May 2000 - - - $ back door - (I) A hardware or software mechanism that (a) provides access to a - system and its resources by other than the usual procedure, (b) - was deliberately left in place by the system's designers or - maintainers, and (c) usually is not publicly known. (See: trap - door.) - - (C) For example, a way to access a computer other than through a - normal login. Such access paths do not necessarily have malicious - intent; e.g., operating systems sometimes are shipped by the - manufacturer with privileged accounts intended for use by field - service technicians or the vendor's maintenance programmers. (See: - trap door.) - - $ back up vs. backup - (I) Verb "back up": To store data for the purpose of creating a - backup copy. (See: archive.) - - (I) Noun/adjective "backup": (1.) A reserve copy of data that is - stored separately from the original, for use if the original - becomes lost or damaged. (See: archive.) (2.) Alternate means to - permit performance of system functions despite a disaster to - system resources. (See: contingency plan.) - - $ baggage - (D) ISDs SHOULD NOT use this term to describe a data element - except when stated as "SET(trademark) baggage" with the following - meaning: - - (O) SET usage: An "opaque encrypted tuple, which is included in a - SET message but appended as external data to the PKCS encapsulated - data. This avoids superencryption of the previously encrypted - tuple, but guarantees linkage with the PKCS portion of the - message." [SET2] - - $ bandwidth - (I) Commonly used to mean the capacity of a communication channel - to pass data through the channel in a given amount of time. - Usually expressed in bits per second. - - $ bank identification number (BIN) - (N) The digits of a credit card number that identify the issuing - bank. (See: primary account number.) - - (O) SET usage: The first six digits of a primary account number. - - - - - - -Shirey Informational [Page 19] - -RFC 2828 Internet Security Glossary May 2000 - - - $ Basic Encoding Rules (BER) - (I) A standard for representing ASN.1 data types as strings of - octets. [X690] (See: Distinguished Encoding Rules.) - - $ bastion host - (I) A strongly protected computer that is in a network protected - by a firewall (or is part of a firewall) and is the only host (or - one of only a few hosts) in the network that can be directly - accessed from networks on the other side of the firewall. - - (C) Filtering routers in a firewall typically restrict traffic - from the outside network to reaching just one host, the bastion - host, which usually is part of the firewall. Since only this one - host can be directly attacked, only this one host needs to be very - strongly protected, so security can be maintained more easily and - less expensively. However, to allow legitimate internal and - external users to access application resources through the - firewall, higher layer protocols and services need to be relayed - and forwarded by the bastion host. Some services (e.g., DNS and - SMTP) have forwarding built in; other services (e.g., TELNET and - FTP) require a proxy server on the bastion host. - - $ BCA - See: brand certification authority. - - $ BCI - See: brand CRL identifier. - - $ Bell-LaPadula Model - (N) A formal, mathematical, state-transition model of security - policy for multilevel-secure computer systems. [Bell] - - (C) The model separates computer system elements into a set of - subjects and a set of objects. To determine whether or not a - subject is authorized for a particular access mode on an object, - the clearance of the subject is compared to the classification of - the object. The model defines the notion of a "secure state", in - which the only permitted access modes of subjects to objects are - in accordance with a specified security policy. It is proven that - each state transition preserves security by moving from secure - state to secure state, thereby proving that the system is secure. - - (C) In this model, a multilevel-secure system satisfies several - rules, including the following: - - - - - - - -Shirey Informational [Page 20] - -RFC 2828 Internet Security Glossary May 2000 - - - - "Confinement property" (also called "*-property", pronounced - "star property"): A subject has write access to an object only - if classification of the object dominates the clearance of the - subject. - - - "Simple security property": A subject has read access to an - object only if the clearance of the subject dominates the - classification of the object. - - - "Tranquillity property": The classification of an object does - not change while the object is being processed by the system. - - $ BER - See: Basic Encoding Rules. - - $ beyond A1 - (O) (1.) Formally, a level of security assurance that is beyond - the highest level of criteria specified by the TCSEC. (2.) - Informally, a level of trust so high that it cannot be provided or - verified by currently available assurance methods, and - particularly not by currently available formal methods. - - $ BIN - See: bank identification number. - - $ bind - (I) To inseparably associate by applying some mechanism, such as - when a CA uses a digital signature to bind together a subject and - a public key in a public-key certificate. - - $ biometric authentication - (I) A method of generating authentication information for a person - by digitizing measurements of a physical characteristic, such as a - fingerprint, a hand shape, a retina pattern, a speech pattern - (voiceprint), or handwriting. - - $ bit - (I) The smallest unit of information storage; a contraction of the - term "binary digit"; one of two symbols--"0" (zero) and "1" (one) - --that are used to represent binary numbers. - - $ BLACK - (I) Designation for information system equipment or facilities - that handle (and for data that contains) only ciphertext (or, - depending on the context, only unclassified information), and for - such data itself. This term derives from U.S. Government COMSEC - terminology. (See: RED, RED/BLACK separation.) - - - - -Shirey Informational [Page 21] - -RFC 2828 Internet Security Glossary May 2000 - - - $ block cipher - (I) An encryption algorithm that breaks plaintext into fixed-size - segments and uses the same key to transform each plaintext segment - into a fixed-size segment of ciphertext. (See: mode, stream - cipher.) - - (C) For example, Blowfish, DEA, IDEA, RC2, and SKIPJACK. However, - a block cipher can be adapted to have a different external - interface, such as that of a stream cipher, by using a mode of - operation to "package" the basic algorithm. - - $ Blowfish - (N) A symmetric block cipher with variable-length key (32 to 448 - bits) designed in 1993 by Bruce Schneier as an unpatented, - license-free, royalty-free replacement for DES or IDEA. [Schn] - - $ brand - (I) A distinctive mark or name that identifies a product or - business entity. - - (O) SET usage: The name of a payment card. Financial institutions - and other companies have founded payment card brands, protect and - advertise the brands, establish and enforce rules for use and - acceptance of their payment cards, and provide networks to - interconnect the financial institutions. These brands combine the - roles of issuer and acquirer in interactions with cardholders and - merchants. [SET1] - - $ brand certification authority (BCA) - (O) SET usage: A CA owned by a payment card brand, such as - MasterCard, Visa, or American Express. [SET2] (See: certification - hierarchy, SET.) - - $ brand CRL identifier (BCI) - (O) SET usage: A digitally signed list, issued by a BCA, of the - names of CAs for which CRLs need to be processed when verifying - signatures in SET messages. [SET2] - - $ break - (I) Cryptographic usage: To successfully perform cryptanalysis and - thus succeed in decrypting data or performing some other - cryptographic function, without initially having knowledge of the - key that the function requires. (This term applies to encrypted - data or, more generally, to a cryptographic algorithm or - cryptographic system.) - - - - - - -Shirey Informational [Page 22] - -RFC 2828 Internet Security Glossary May 2000 - - - $ bridge - (I) A computer that is a gateway between two networks (usually two - LANs) at OSI layer 2. (See: router.) - - $ British Standard 7799 - (N) Part 1 is a standard code of practice and provides guidance on - how to secure an information system. Part 2 specifies the - management framework, objectives, and control requirements for - information security management systems [B7799]. The certification - scheme works like ISO 9000. It is in use in the UK, the - Netherlands, Australia, and New Zealand and might be proposed as - an ISO standard or adapted to be part of the Common Criteria. - - $ browser - (I) An client computer program that can retrieve and display - information from servers on the World Wide Web. - - (C) For example, Netscape's Navigator and Communicator, and - Microsoft's Explorer. - - $ brute force - (I) A cryptanalysis technique or other kind of attack method - involving an exhaustive procedure that tries all possibilities, - one-by-one. - - (C) For example, for ciphertext where the analyst already knows - the decryption algorithm, a brute force technique to finding the - original plaintext is to decrypt the message with every possible - key. - - $ BS7799 - See: British Standard 7799. - - $ byte - (I) A fundamental unit of computer storage; the smallest - addressable unit in a computer's architecture. Usually holds one - character of information and, today, usually means eight bits. - (See: octet.) - - (C) Larger than a "bit", but smaller than a "word". Although - "byte" almost always means "octet" today, bytes had other sizes - (e.g., six bits, nine bits) in earlier computer architectures. - - $ CA - See: certification authority. - - - - - - -Shirey Informational [Page 23] - -RFC 2828 Internet Security Glossary May 2000 - - - $ CA certificate - (I) "A [digital] certificate for one CA issued by another CA." - [X509] - - (C) That is, a digital certificate whose holder is able to issue - digital certificates. A v3 X.509 public-key certificate may have a - "basicConstraints" extension containing a "cA" value that - specifically "indicates whether or not the public key may be used - to verify certificate signatures." - - $ call back - (I) An authentication technique for terminals that remotely access - a computer via telephone lines. The host system disconnects the - caller and then calls back on a telephone number that was - previously authorized for that terminal. - - $ capability - (I) A token, usually an unforgeable data value (sometimes called a - "ticket") that gives the bearer or holder the right to access a - system resource. Possession of the token is accepted by a system - as proof that the holder has been authorized to access the - resource named or indicated by the token. (See: access control - list, credential, digital certificate.) - - (C) This concept can be implemented as a digital certificate. - (See: attribute certificate.) - - $ CAPI - See: cryptographic application programming interface. - - $ CAPSTONE chip - (N) An integrated circuit (the Mykotronx, Inc. MYK-82) with a Type - II cryptographic processor that implements SKIPJACK, KEA, DSA, - SHA, and basic mathematical functions to support asymmetric - cryptography, and includes the key escrow feature of the CLIPPER - chip. (See: FORTEZZA card.) - - $ card - See: cryptographic card, FORTEZZA card, payment card, PC card, - smart card, token. - - $ card backup - See: token backup. - - $ card copy - See: token copy. - - - - - -Shirey Informational [Page 24] - -RFC 2828 Internet Security Glossary May 2000 - - - $ card restore - See: token restore. - - $ cardholder - (I) An entity that has been issued a card. - - (O) SET usage: "The holder of a valid payment card account and - user of software supporting electronic commerce." [SET2] A - cardholder is issued a payment card by an issuer. SET ensures that - in the cardholder's interactions with merchants, the payment card - account information remains confidential. [SET1] - - $ cardholder certificate - (O) SET usage: A digital certificate that is issued to a - cardholder upon approval of the cardholder's issuing financial - institution and that is transmitted to merchants with purchase - requests and encrypted payment instructions, carrying assurance - that the account number has been validated by the issuing - financial institution and cannot be altered by a third party. - [SET1] - - $ cardholder certification authority (CCA) - (O) SET usage: A CA responsible for issuing digital certificates - to cardholders and operated on behalf of a payment card brand, an - issuer, or another party according to brand rules. A CCA maintains - relationships with card issuers to allow for the verification of - cardholder accounts. A CCA does not issue a CRL but does - distribute CRLs issued by root CAs, brand CAs, geopolitical CAs, - and payment gateway CAs. [SET2] - - $ CAST - (N) A design procedure for symmetric encryption algorithms, and a - resulting family of algorithms, invented by C.A. (Carlisle Adams) - and S.T. (Stafford Tavares). [R2144, R2612] - - $ category - (I) A grouping of sensitive information items to which a non- - hierarchical restrictive security label is applied to increase - protection of the data. (See: compartment.) - - $ CAW - See: certification authority workstation. - - $ CBC - See: cipher block chaining. - - $ CCA - See: cardholder certification authority. - - - -Shirey Informational [Page 25] - -RFC 2828 Internet Security Glossary May 2000 - - - $ CCITT - (N) Acronym for French translation of International Telephone and - Telegraph Consultative Committee. Now renamed ITU-T. - - $ CERT - See: computer emergency response team. - - $ certificate - (I) General English usage: A document that attests to the truth of - something or the ownership of something. - - (C) Security usage: See: capability, digital certificate. - - (C) PKI usage: See: attribute certificate, public-key certificate. - - $ certificate authority - (D) ISDs SHOULD NOT use this term because it looks like sloppy use - of "certification authority", which is the term standardized by - X.509. - - $ certificate chain - (D) ISDs SHOULD NOT use this term because it duplicates the - meaning of a standardized term. Instead, use "certification path". - - $ certificate chain validation - (D) ISDs SHOULD NOT use this term because it duplicates the - meaning of standardized terms and mixes concepts in a potentially - misleading way. Instead, use "certificate validation" or "path - validation", depending on what is meant. (See: validate vs. - verify.) - - $ certificate creation - (I) The act or process by which a CA sets the values of a digital - certificate's data fields and signs it. (See: issue.) - - $ certificate expiration - (I) The event that occurs when a certificate ceases to be valid - because its assigned lifetime has been exceeded. (See: certificate - revocation, validity period.) - - $ certificate extension - See: extension. - - - - - - - - - -Shirey Informational [Page 26] - -RFC 2828 Internet Security Glossary May 2000 - - - $ certificate holder - (D) ISDs SHOULD NOT use this term as a synonym for the subject of - a digital certificate because the term is potentially ambiguous. - For example, the term could also refer to a system entity, such as - a repository, that simply has possession of a copy of the - certificate. (See: certificate owner.) - - $ certificate management - (I) The functions that a CA may perform during the life cycle of a - digital certificate, including the following: - - - Acquire and verify data items to bind into the certificate. - - Encode and sign the certificate. - - Store the certificate in a directory or repository. - - Renew, rekey, and update the certificate. - - Revoke the certificate and issue a CRL. - - (See: archive management, certificate management, key management, - security architecture, token management.) - - $ certificate owner - (D) ISDs SHOULD NOT use this term as a synonym for the subject of - a digital certificate because the term is potentially ambiguous. - For example, the term could also refer to a system entity, such as - a corporation, that has acquired a certificate to operate some - other entity, such as a Web server. (See: certificate holder.) - - $ certificate policy - (I) "A named set of rules that indicates the applicability of a - certificate to a particular community and/or class of application - with common security requirements." [X509] (See: certification - practice statement.) - - (C) A certificate policy can help a certificate user decide - whether a certificate should be trusted in a particular - application. "For example, a particular certificate policy might - indicate applicability of a type of certificate for the - authentication of electronic data interchange transactions for the - trading goods within a given price range." [R2527] - - (C) A v3 X.509 public-key certificate may have a - "certificatePolicies" extension that lists certificate policies, - recognized by the issuing CA, that apply to the certificate and - govern its use. Each policy is denoted by an object identifier and - may optionally have certificate policy qualifiers. - - - - - - -Shirey Informational [Page 27] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) SET usage: Every SET certificate specifies at least one - certificate policy, that of the SET root CA. SET uses certificate - policy qualifiers to point to the actual policy statement and to - add qualifying policies to the root policy. (See: SET qualifier.) - - $ certificate policy qualifier - (I) Information that pertains to a certificate policy and is - included in a "certificatePolicies" extension in a v3 X.509 - public-key certificate. - - $ certificate reactivation - (I) The act or process by which a digital certificate, which a CA - has designated for revocation but not yet listed on a CRL, is - returned to the valid state. - - $ certificate rekey - (I) The act or process by which an existing public-key certificate - has its public key value changed by issuing a new certificate with - a different (usually new) public key. (See: certificate renewal, - certificate update, rekey.) - - (C) For an X.509 public-key certificate, the essence of rekey is - that the subject stays the same and a new public key is bound to - that subject. Other changes are made, and the old certificate is - revoked, only as required by the PKI and CPS in support of the - rekey. If changes go beyond that, the process is a "certificate - update". - - (O) MISSI usage: To rekey a MISSI X.509 public-key certificate - means that the issuing authority creates a new certificate that is - identical to the old one, except the new one has a new, different - KEA key; or a new, different DSS key; or new, different KEA and - DSS keys. The new certificate also has a different serial number - and may have a different validity period. A new key creation date - and maximum key lifetime period are assigned to each newly - generated key. If a new KEA key is generated, that key is assigned - a new KMID. The old certificate remains valid until it expires, - but may not be further renewed, rekeyed, or updated. - - $ certificate renewal - (I) The act or process by which the validity of the data binding - asserted by an existing public-key certificate is extended in time - by issuing a new certificate. (See: certificate rekey, certificate - update.) - - (C) For an X.509 public-key certificate, this term means that the - validity period is extended (and, of course, a new serial number - is assigned) but the binding of the public key to the subject and - - - -Shirey Informational [Page 28] - -RFC 2828 Internet Security Glossary May 2000 - - - to other data items stays the same. The other data items are - changed, and the old certificate is revoked, only as required by - the PKI and CPS to support the renewal. If changes go beyond that, - the process is a "certificate rekey" or "certificate update". - - $ certificate request - (D) ISDs SHOULD NOT use this term because it looks like imprecise - use of a term standardized by PKCS #10 and used in PKIX. Instead, - use the standard term, "certification request". - - $ certificate revocation - (I) The event that occurs when a CA declares that a previously - valid digital certificate issued by that CA has become invalid; - usually stated with a revocation date. - - (C) In X.509, a revocation is announced to potential certificate - users by issuing a CRL that mentions the certificate. Revocation - and listing on a CRL is only necessary before certificate - expiration. - - $ certificate revocation list (CRL) - (I) A data structure that enumerates digital certificates that - have been invalidated by their issuer prior to when they were - scheduled to expire. (See: certificate expiration, X.509 - certificate revocation list.) - - (O) "A signed list indicating a set of certificates that are no - longer considered valid by the certificate issuer. After a - certificate appears on a CRL, it is deleted from a subsequent CRL - after the certificate's expiry. CRLs may be used to identify - revoked public-key certificates or attribute certificates and may - represent revocation of certificates issued to authorities or to - users. The term CRL is also commonly used as a generic term - applying to all the different types of revocation lists, including - CRLs, ARLs, ACRLs, etc." [FPDAM] - - $ certificate revocation tree - (I) A mechanism for distributing notice of certificate - revocations; uses a tree of hash results that is signed by the - tree's issuer. Offers an alternative to issuing a CRL, but is not - supported in X.509. (See: certificate status responder.) - - $ certificate serial number - (I) An integer value that (a) is associated with, and may be - carried in, a digital certificate; (b) is assigned to the - certificate by the certificate's issuer; and (c) is unique among - all the certificates produced by that issuer. - - - - -Shirey Informational [Page 29] - -RFC 2828 Internet Security Glossary May 2000 - - - (O) "An integer value, unique within the issuing CA, which is - unambiguously associated with a certificate issued by that CA." - [X509] - - $ certificate status responder - (N) FPKI usage: A trusted on-line server that acts for a CA to - provide authenticated certificate status information to - certificate users. [FPKI] Offers an alternative to issuing a CRL, - but is not supported in X.509. (See: certificate revocation tree.) - - $ certificate update - (I) The act or process by which non-key data items bound in an - existing public-key certificate, especially authorizations granted - to the subject, are changed by issuing a new certificate. (See: - certificate rekey, certificate renewal.) - - (C) For an X.509 public-key certificate, the essence of this - process is that fundamental changes are made in the data that is - bound to the public key, such that it is necessary to revoke the - old certificate. (Otherwise, the process is only a "certificate - rekey" or "certificate renewal".) - - $ certificate user - (I) A system entity that depends on the validity of information - (such as another entity's public key value) provided by a digital - certificate. (See: relying party.) - - (O) "An entity that needs to know, with certainty, the public key - of another entity." [X509] - - (C) The system entity may be a human being or an organization, or - a device or process under the control of a human or an - organization. - - (D) ISDs SHOULD NOT use this term as a synonym for the "subject" - of a certificate. - - $ certificate validation - (I) An act or process by which a certificate user establishes that - the assertions made by a digital certificate can be trusted. (See: - valid certificate, validate vs. verify.) - - (O) "The process of ensuring that a certificate is valid including - possibly the construction and processing of a certification path, - and ensuring that all certificates in that path have not expired - or been revoked." [FPDAM] - - - - - -Shirey Informational [Page 30] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) To validate a certificate, a certificate user checks that the - certificate is properly formed and signed and currently in force: - - - Checks the signature: Employs the issuer's public key to verify - the digital signature of the CA who issued the certificate in - question. If the verifier obtains the issuer's public key from - the issuer's own public-key certificate, that certificate - should be validated, too. That validation may lead to yet - another certificate to be validated, and so on. Thus, in - general, certificate validation involves discovering and - validating a certification path. - - - Checks the syntax and semantics: Parses the certificate's - syntax and interprets its semantics, applying rules specified - for and by its data fields, such as for critical extensions in - an X.509 certificate. - - - Checks currency and revocation: Verifies that the certificate - is currently in force by checking that the current date and - time are within the validity period (if that is specified in - the certificate) and that the certificate is not listed on a - CRL or otherwise announced as invalid. (CRLs themselves require - a similar validation process.) - - $ certification - (I) Information system usage: Technical evaluation (usually made - in support of an accreditation action) of an information system's - security features and other safeguards to establish the extent to - which the system's design and implementation meet specified - security requirements. [FP102] (See: accreditation.) - - (I) Digital certificate usage: The act or process of vouching for - the truth and accuracy of the binding between data items in a - certificate. (See: certify.) - - (I) Public key usage: The act or process of vouching for the - ownership of a public key by issuing a public-key certificate that - binds the key to the name of the entity that possesses the - matching private key. In addition to binding a key to a name, a - public-key certificate may bind those items to other restrictive - or explanatory data items. (See: X.509 public-key certificate.) - - (O) SET usage: "The process of ascertaining that a set of - requirements or criteria has been fulfilled and attesting to that - fact to others, usually with some written instrument. A system - that has been inspected and evaluated as fully compliant with the - SET protocol by duly authorized parties and process would be said - to have been certified compliant." [SET2] - - - -Shirey Informational [Page 31] - -RFC 2828 Internet Security Glossary May 2000 - - - $ certification authority (CA) - (I) An entity that issues digital certificates (especially X.509 - certificates) and vouches for the binding between the data items - in a certificate. - - (O) "An authority trusted by one or more users to create and - assign certificates. Optionally, the certification authority may - create the user's keys." [X509] - - (C) Certificate users depend on the validity of information - provided by a certificate. Thus, a CA should be someone that - certificate users trust, and usually holds an official position - created and granted power by a government, a corporation, or some - other organization. A CA is responsible for managing the life - cycle of certificates (see: certificate management) and, depending - on the type of certificate and the CPS that applies, may be - responsible for the life cycle of key pairs associated with the - certificates (see: key management). - - $ certification authority workstation (CAW) - (I) A computer system that enables a CA to issue digital - certificates and supports other certificate management functions - as required. - - $ certification hierarchy - (I) A tree-structured (loop-free) topology of relationships among - CAs and the entities to whom the CAs issue public-key - certificates. (See: hierarchical PKI.) - - (C) In this structure, one CA is the top CA, the highest level of - the hierarchy. (See: root, top CA.) The top CA may issue public- - key certificates to one or more additional CAs that form the - second highest level. Each of these CAs may issue certificates to - more CAs at the third highest level, and so on. The CAs at the - second-lowest of the hierarchy issue certificates only to non-CA - entities, called "end entities" that form the lowest level. (See: - end entity.) Thus, all certification paths begin at the top CA and - descend through zero or more levels of other CAs. All certificate - users base path validations on the top CA's public key. - - (O) MISSI usage: A MISSI certification hierarchy has three or four - levels of CAs: - - - A CA at the highest level, the top CA, is a "policy approving - authority". - - A CA at the second-highest level is a "policy creation - authority". - - - - -Shirey Informational [Page 32] - -RFC 2828 Internet Security Glossary May 2000 - - - - A CA at the third-highest level is a local authority called a - "certification authority". - - A CA at the fourth-highest (optional) level is a "subordinate - certification authority". - - (O) PEM usage: A PEM certification hierarchy has three levels of - CAs [R1422]: - - - The highest level is the "Internet Policy Registration - Authority". - - A CA at the second-highest level is a "policy certification - authority". - - A CA at the third-highest level is a "certification authority". - - (O) SET usage: A SET certification hierarchy has three or four - levels of CAs: - - - The highest level is a "SET root CA". - - A CA at the second-highest level is a "brand certification - authority". - - A CA at the third-highest (optional) level is a "geopolitical - certification authority". - - A CA at the fourth-highest level is a "cardholder CA", a - "merchant CA", or a "payment gateway CA". - - $ certification path - (I) An ordered sequence of public-key certificates (or a sequence - of public-key certificates followed by one attribute certificate) - that enables a certificate user to verify the signature on the - last certificate in the path, and thus enables the user to obtain - a certified public key (or certified attributes) of the entity - that is the subject of that last certificate. (See: certificate - validation, valid certificate.) - - (O) "An ordered sequence of certificates of objects in the [X.500 - Directory Information Tree] which, together with the public key of - the initial object in the path, can be processed to obtain that of - the final object in the path." [X509, R2527] - - (C) The path is the "list of certificates needed to allow a - particular user to obtain the public key of another." [X509] The - list is "linked" in the sense that the digital signature of each - certificate (except the first) is verified by the public key - contained in the preceding certificate; i.e., the private key used - to sign a certificate and the public key contained in the - preceding certificate form a key pair owned by the entity that - signed. - - - - -Shirey Informational [Page 33] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) In the X.509 quotation in the previous "C" paragraph, the word - "particular" points out that a certification path that can be - validated by one certificate user might not be able to be - validated by another. That is because either the first certificate - should be a trusted certificate (it might be a root certificate) - or the signature on the first certificate should be verified by a - trusted key (it might be a root key), but such trust is defined - relative to each user, not absolutely for all users. - - $ certification policy - (D) ISDs SHOULD NOT use this term. Instead, use either - "certificate policy" or "certification practice statement", - depending on what is meant. - - $ certification practice statement (CPS) - (I) "A statement of the practices which a certification authority - employs in issuing certificates." [ABA96, R2527] (See: certificate - policy.) - - (C) A CPS is a published security policy that can help a - certificate user to decide whether a certificate issued by a - particular CA can be trusted enough to use in a particular - application. A CPS may be (a) a declaration by a CA of the details - of the system and practices it employs in its certificate - management operations, (b) part of a contract between the CA and - an entity to whom a certificate is issued, (c) a statute or - regulation applicable to the CA, or (d) a combination of these - types involving multiple documents. [ABA] - - (C) A CPS is usually more detailed and procedurally oriented than - a certificate policy. A CPS applies to a particular CA or CA - community, while a certificate policy applies across CAs or - communities. A CA with a single CPS may support multiple - certificate policies, which may be used for different application - purposes or by different user communities. Multiple CAs, each with - a different CPS, may support the same certificate policy. [R2527] - - $ certification request - (I) A algorithm-independent transaction format, defined by PCKS - #10 and used in PKIX, that contains a DN, a public key, and - optionally a set of attributes, collectively signed by the entity - requesting certification, and sent to a CA, which transforms the - request to an X.509 public-key certificate or another type of - certificate. - - - - - - - -Shirey Informational [Page 34] - -RFC 2828 Internet Security Glossary May 2000 - - - $ certify - 1. (I) Issue a digital certificate and thus vouch for the truth, - accuracy, and binding between data items in the certificate (e.g., - see: X.509 public key certificate), such as the identity of the - certificate's subject and the ownership of a public key. (See: - certification.) - - (C) To "certify a public key" means to issue a public-key - certificate that vouches for the binding between the certificate's - subject and the key. - - 2. (I) The act by which a CA employs measures to verify the truth, - accuracy, and binding between data items in a digital certificate. - - (C) A description of the measures used for verification should be - included in the CA's CPS. - - $ CFB - See: cipher feedback. - - $ Challenge Handshake Authentication Protocol (CHAP) - (I) A peer entity authentication method for PPP, using a randomly- - generated challenge and requiring a matching response that depends - on a cryptographic hash of the challenge and a secret key. [R1994] - (See: challenge-response, PAP.) - - $ challenge-response - (I) An authentication process that verifies an identity by - requiring correct authentication information to be provided in - response to a challenge. In a computer system, the authentication - information is usually a value that is required to be computed in - response to an unpredictable challenge value. - - $ Challenge-Response Authentication Mechanism (CRAM) - (I) IMAP4 usage: A mechanism [R2195], intended for use with IMAP4 - AUTHENTICATE, by which an IMAP4 client uses a keyed hash [R2104] - to authenticate itself to an IMAP4 server. (See: POP3 APOP.) - - (C) The server includes a unique timestamp in its ready response - to the client. The client replies with the client's name and the - hash result of applying MD5 to a string formed from concatenating - the timestamp with a shared secret that is known only to the - client and the server. - - $ channel - (I) An information transfer path within a system. (See: covert - channel.) - - - - -Shirey Informational [Page 35] - -RFC 2828 Internet Security Glossary May 2000 - - - $ CHAP - See: Challenge Handshake Authentication Protocol. - - $ checksum - (I) A value that (a) is computed by a function that is dependent - on the contents of a data object and (b) is stored or transmitted - together with the object, for the purpose of detecting changes in - the data. (See: cyclic redundancy check, data integrity service, - error detection code, hash, keyed hash, protected checksum.) - - (C) To gain confidence that a data object has not been changed, an - entity that later uses the data can compute a checksum and compare - it with the checksum that was stored or transmitted with the - object. - - (C) Computer systems and networks employ checksums (and other - mechanisms) to detect accidental changes in data. However, active - wiretapping that changes data could also change an accompanying - checksum to match the changed data. Thus, some checksum functions - by themselves are not good countermeasures for active attacks. To - protect against active attacks, the checksum function needs to be - well-chosen (see: cryptographic hash), and the checksum result - needs to be cryptographically protected (see: digital signature, - keyed hash). - - $ chosen-ciphertext attack - (I) A cryptanalysis technique in which the analyst tries to - determine the key from knowledge of plaintext that corresponds to - ciphertext selected (i.e., dictated) by the analyst. - - $ chosen-plaintext attack - (I) A cryptanalysis technique in which the analyst tries to - determine the key from knowledge of ciphertext that corresponds to - plaintext selected (i.e., dictated) by the analyst. - - $ CIAC - See: Computer Incident Advisory Capability. - - $ CIK - See: cryptographic ignition key. - - $ cipher - (I) A cryptographic algorithm for encryption and decryption. - - $ cipher block chaining (CBC) - (I) An block cipher mode that enhances electronic codebook mode by - chaining together blocks of ciphertext it produces. [FP081] (See: - [R1829], [R2451].) - - - -Shirey Informational [Page 36] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) This mode operates by combining (exclusive OR-ing) the - algorithm's ciphertext output block with the next plaintext block - to form the next input block for the algorithm. - - $ cipher feedback (CFB) - (I) An block cipher mode that enhances electronic code book mode - by chaining together the blocks of ciphertext it produces and - operating on plaintext segments of variable length less than or - equal to the block length. [FP081] - - (C) This mode operates by using the previously generated - ciphertext segment as the algorithm's input (i.e., by "feeding - back" the ciphertext) to generate an output block, and then - combining (exclusive OR-ing) that output block with the next - plaintext segment (block length or less) to form the next - ciphertext segment. - - $ ciphertext - (I) Data that has been transformed by encryption so that its - semantic information content (i.e., its meaning) is no longer - intelligible or directly available. (See: cleartext, plaintext.) - - (O) "Data produced through the use of encipherment. The semantic - content of the resulting data is not available." [I7498 Part 2] - - $ ciphertext-only attack - (I) A cryptanalysis technique in which the analyst tries to - determine the key solely from knowledge of intercepted ciphertext - (although the analyst may also know other clues, such as the - cryptographic algorithm, the language in which the plaintext was - written, the subject matter of the plaintext, and some probable - plaintext words.) - - $ CIPSO - See: Common IP Security Option. - - $ CKL - See: compromised key list. - - $ class 2, 3, 4, or 5 - (O) U.S. Department of Defense usage: Levels of PKI assurance - based on risk and value of information to be protected [DOD3]: - - - Class 2: For handling low-value information (unclassified, not - mission-critical, or low monetary value) or protection of - system-high information in low- to medium-risk environment. - - - - - -Shirey Informational [Page 37] - -RFC 2828 Internet Security Glossary May 2000 - - - - Class 3: For handling medium-value information in low- to - medium-risk environment. Typically requires identification of a - system entity as a legal person, rather than merely a member of - an organization. - - - Class 4: For handling medium- to high-value information in any - environment. Typically requires identification of an entity as - a legal person, rather than merely a member of an organization, - and a cryptographic hardware token for protection of keying - material. - - - Class 5: For handling high-value information in a high-risk - environment. - - $ classification - $ classification level - (I) (1.) A grouping of classified information to which a - hierarchical, restrictive security label is applied to increase - protection of the data. (2.) The level of protection that is - required to be applied to that information. (See: security level.) - - $ classified - (I) Refers to information (stored or conveyed, in any form) that - is formally required by a security policy to be given data - confidentiality service and to be marked with a security label - (which in some cases might be implicit) to indicate its protected - status. (See: unclassified.) - - (C) The term is mainly used in government, especially in the - military, although the concept underlying the term also applies - outside government. In the U.S. Department of Defense, for - example, it means information that has been determined pursuant to - Executive Order 12958 ("Classified National Security Information", - 20 April 1995) or any predecessor order to require protection - against unauthorized disclosure and is marked to indicate its - classified status when in documentary form. - - $ clean system - (I) A computer system in which the operating system and - application system software and files have just been freshly - installed from trusted software distribution media. - - (C) A clean system is not necessarily in a secure state. - - $ clearance - See: security clearance. - - - - - -Shirey Informational [Page 38] - -RFC 2828 Internet Security Glossary May 2000 - - - $ clearance level - (I) The security level of information to which a security - clearance authorizes a person to have access. - - $ cleartext - (I) Data in which the semantic information content (i.e., the - meaning) is intelligible or is directly available. (See: - plaintext.) - - (O) "Intelligible data, the semantic content of which is - available." [I7498 Part 2] - - (D) ISDs SHOULD NOT use this term as a synonym for "plaintext", - the input to an encryption operation, because the plaintext input - to encryption may itself be ciphertext that was output from - another operation. (See: superencryption.) - - $ client - (I) A system entity that requests and uses a service provided by - another system entity, called a "server". (See: server.) - - (C) Usually, the requesting entity is a computer process, and it - makes the request on behalf of a human user. In some cases, the - server may itself be a client of some other server. - - $ CLIPPER chip - (N) The Mykotronx, Inc. MYK-82, an integrated microcircuit with a - cryptographic processor that implements the SKIPJACK encryption - algorithm and supports key escrow. (See: CAPSTONE, Escrowed - Encryption Standard.) - - (C) The key escrow scheme for a chip involves a SKIPJACK key - common to all chips that protects the unique serial number of the - chip, and a second SKIPJACK key unique to the chip that protects - all data encrypted by the chip. The second key is escrowed as - split key components held by NIST and the U.S. Treasury - Department. - - $ closed security environment - (O) U.S. Department of Defense usage: A system environment that - meets both of the following conditions: (a) Application developers - (including maintainers) have sufficient clearances and - authorizations to provide an acceptable presumption that they have - not introduced malicious logic. (b) Configuration control provides - sufficient assurance that system applications and the equipment - they run on are protected against the introduction of malicious - logic prior to and during the operation of applications. [NCS04] - (See: open security environment.) - - - -Shirey Informational [Page 39] - -RFC 2828 Internet Security Glossary May 2000 - - - $ code - (I) noun: A system of symbols used to represent information, which - might originally have some other representation. (See: encode.) - - (D) ISDs SHOULD NOT use this term as synonym for the following: - (a) "cipher", "hash", or other words that mean "a cryptographic - algorithm"; (b) "ciphertext"; or (c) "encrypt", "hash", or other - words that refer to applying a cryptographic algorithm. - - (D) ISDs SHOULD NOT this word as an abbreviation for the following - terms: country code, cyclic redundancy code, Data Authentication - Code, error detection code, Message Authentication Code, object - code, or source code. To avoid misunderstanding, use the fully - qualified term, at least at the point of first usage. - - $ color change - (I) In a system that is being operated in periods processing mode, - the act of purging all information from one processing period and - then changing over to the next processing period. - - $ Common Criteria - $ Common Criteria for Information Technology Security - (N) "The Common Criteria" is a standard for evaluating information - technology products and systems, such as operating systems, - computer networks, distributed systems, and applications. It - states requirements for security functions and for assurance - measures. [CCIB] - - (C) Canada, France, Germany, the Netherlands, the United Kingdom, - and the United States (NIST and NSA) began developing this - standard in 1993, based on the European ITSEC, the Canadian - Trusted Computer Product Evaluation Criteria (CTCPEC), and the - U.S. "Federal Criteria for Information Technology Security" (FC) - and its precursor, the TCSEC. Work was done in cooperation with - ISO/IEC Joint Technical Committee 1 (Information Technology), - Subcommittee 27 (Security Techniques), Working Group 3 (Security - Criteria). Version 2.1 of the Criteria is equivalent to ISO's - International Standard 15408 [I15408]. The U.S. Government intends - that this standard eventually will supersede both the TCSEC and - FIPS PUB 140-1. (See: NIAP.) - - (C) The standard addresses data confidentiality, data integrity, - and availability and may apply to other aspects of security. It - focuses on threats to information arising from human activities, - malicious or otherwise, but may apply to non-human threats. It - applies to security measures implemented in hardware, firmware, or - software. It does not apply to (a) administrative security not - related directly to technical security, (b) technical physical - - - -Shirey Informational [Page 40] - -RFC 2828 Internet Security Glossary May 2000 - - - aspects of security such as electromagnetic emanation control, (c) - evaluation methodology or administrative and legal framework under - which the criteria may be applied, (d) procedures for use of - evaluation results, or (e) assessment of inherent qualities of - cryptographic algorithms. - - $ Common IP Security Option (CIPSO) - See: (secondary definition under) Internet Protocol Security - Option. - - $ common name - (I) A character string that (a) may be a part of the X.500 DN of a - Directory object ("commonName" attribute), (b) is a (possibly - ambiguous) name by which the object is commonly known in some - limited scope (such as an organization), and (c) conforms to the - naming conventions of the country or culture with which it is - associated. [X520] (See: ("subject" and "issuer" under) X.509 - public-key certificate.) - - (C) For example, "Dr. E. F. Moore", "The United Nations", or - "12-th Floor Laser Printer". - - $ communication security (COMSEC) - (I) Measures that implement and assure security services in a - communication system, particularly those that provide data - confidentiality and data integrity and that authenticate - communicating entities. - - (C) Usually understood to include cryptographic algorithms and key - management methods and processes, devices that implement them, and - the life cycle management of keying material and devices. - - $ community string - (I) A community name in the form of an octet string that serves as - a cleartext password in SNMP version 1. [R1157] - - $ compartment - (I) A grouping of sensitive information items that require special - access controls beyond those normally provided for the basic - classification level of the information. (See: category.) - - (C) The term is usually understood to include the special handling - procedures to be used for the information. - - $ compromise - See: data compromise, security compromise. - - - - - -Shirey Informational [Page 41] - -RFC 2828 Internet Security Glossary May 2000 - - - $ compromised key list (CKL) - (O) MISSI usage: A list that identifies keys for which - unauthorized disclosure or alteration may have occurred. (See: - compromise.) - - (C) A CKL is issued by an CA, like a CRL is issued. But a CKL - lists only KMIDs, not subjects that hold the keys, and not - certificates in which the keys are bound. - - $ COMPUSEC - See: computer security. - - $ computer emergency response team (CERT) - (I) An organization that studies computer and network INFOSEC in - order to provide incident response services to victims of attacks, - publish alerts concerning vulnerabilities and threats, and offer - other information to help improve computer and network security. - (See: CSIRT, security incident.) - - (C) For example, the CERT Coordination Center at Carnegie-Mellon - University (sometimes called "the" CERT) and the Computer Incident - Advisory Capability. - - $ Computer Incident Advisory Capability (CIAC) - (N) A computer emergency response team in the U.S. Department of - Energy. - - $ computer network - (I) A collection of host computers together with the subnetwork or - internetwork through which they can exchange data. - - (C) This definition is intended to cover systems of all sizes and - types, ranging from the complex Internet to a simple system - composed of a personal computer dialing in as a remote terminal of - another computer. - - $ computer security (COMPUSEC) - (I) Measures that implement and assure security services in a - computer system, particularly those that assure access control - service. - - (C) Usually understood to include functions, features, and - technical characteristics of computer hardware and software, - especially operating systems. - - - - - - - -Shirey Informational [Page 42] - -RFC 2828 Internet Security Glossary May 2000 - - - $ computer security incident response team (CSIRT) - (I) An organization "that coordinates and supports the response to - security incidents that involve sites within a defined - constituency." [R2350] (See: CERT, FIRST, security incident.) - - (C) To be considered a CSIRT, an organization must do as follows: - - - Provide a (secure) channel for receiving reports about - suspected security incidents. - - Provide assistance to members of its constituency in handling - the incidents. - - Disseminate incident-related information to its constituency - and other involved parties. - - $ computer security object - (I) The definition or representation of a resource, tool, or - mechanism used to maintain a condition of security in computerized - environments. Includes many elements referred to in standards that - are either selected or defined by separate user communities. - [CSOR] (See: object identifier, Computer Security Objects - Register.) - - $ Computer Security Objects Register (CSOR) - (N) A service operated by NIST is establishing a catalog for - computer security objects to provide stable object definitions - identified by unique names. The use of this register will enable - the unambiguous specification of security parameters and - algorithms to be used in secure data exchanges. - - (C) The CSOR follows registration guidelines established by the - international standards community and ANSI. Those guidelines - establish minimum responsibilities for registration authorities - and assign the top branches of an international registration - hierarchy. Under that international registration hierarchy the - CSOR is responsible for the allocation of unique identifiers under - the branch {joint-iso-ccitt(2) country(16) us(840) gov(101) - csor(3)}. - - $ COMSEC - See: communication security. - - $ confidentiality - See: data confidentiality. - - $ configuration control - (I) The process of regulating changes to hardware, firmware, - software, and documentation throughout the development and - operational life of a system. (See: administrative security.) - - - -Shirey Informational [Page 43] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) Configuration control helps protect against unauthorized or - malicious alteration of a system and thus provides assurance of - system integrity. (See: malicious logic.) - - $ confinement property - See: (secondary definition under) Bell-LaPadula Model. - - $ connectionless data integrity service - (I) A security service that provides data integrity service for an - individual IP datagram, by detecting modification of the datagram, - without regard to the ordering of the datagram in a stream of - datagrams. - - (C) A connection-oriented data integrity service would be able to - detect lost or reordered datagrams within a stream of datagrams. - - $ contingency plan - (I) A plan for emergency response, backup operations, and post- - disaster recovery in a system as part of a security program to - ensure availability of critical system resources and facilitate - continuity of operations in a crisis. [NCS04] (See: availability.) - - $ controlled security mode - (D) ISDs SHOULD NOT use this term. It was defined in an earlier - version of the U.S. Department of Defense policy that regulates - system accreditation, but was subsumed by "partitioned security - mode" in the current version. [DOD2] - - (C) The term refers to a mode of operation of an information - system, wherein at least some users with access to the system have - neither a security clearance nor a need-to-know for all classified - material contained in the system. However, separation and control - of users and classified material on the basis, respectively, of - clearance and classification level are not essentially under - operating system control like they are in "multilevel security - mode". - - (C) Controlled mode was intended to encourage ingenuity in meeting - the security requirements of Defense policy in ways less - restrictive than "dedicated security mode" and "system high - security mode", but at a level of risk lower than that generally - associated with the true "multilevel security mode". This was to - be accomplished by implementation of explicit augmenting measures - to reduce or remove a substantial measure of system software - vulnerability together with specific limitation of the security - clearance levels of users permitted concurrent access to the - system. - - - - -Shirey Informational [Page 44] - -RFC 2828 Internet Security Glossary May 2000 - - - $ cookie - (I) access control usage: A synonym for "capability" or "ticket" - in an access control system. - - (I) IPsec usage: Data exchanged by ISAKMP to prevent certain - denial-of-service attacks during the establishment of a security - association. - - (I) HTTP usage: Data exchanged between an HTTP server and a - browser (a client of the server) to store state information on the - client side and retrieve it later for server use. - - (C) An HTTP server, when sending data to a client, may send along - a cookie, which the client retains after the HTTP connection - closes. A server can use this mechanism to maintain persistent - client-side state information for HTTP-based applications, - retrieving the state information in later connections. A cookie - may include a description of the range of URLs for which the state - is valid. Future requests made by the client in that range will - also send the current value of the cookie to the server. Cookies - can be used to generate profiles of web usage habits, and thus may - infringe on personal privacy. - - $ Coordinated Universal Time (UTC) - (N) UTC is derived from International Atomic Time (TAI) by adding - a number of leap seconds. The International Bureau of Weights and - Measures computes TAI once each month by averaging data from many - laboratories. (See: GeneralizedTime, UTCTime.) - - $ copy - See: card copy. - - $ correctness integrity - (I) Accuracy and consistency of the information that data values - represent, rather than of the data itself. Closely related to - issues of accountability and error handling. (See: data integrity, - source integrity.) - - $ correctness proof - (I) A mathematical proof of consistency between a specification - for system security and the implementation of that specification. - (See: formal specification.) - - $ countermeasure - (I) An action, device, procedure, or technique that reduces a - threat, a vulnerability, or an attack by eliminating or preventing - it, by minimizing the harm it can cause, or by discovering and - reporting it so that corrective action can be taken. - - - -Shirey Informational [Page 45] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) In an Internet protocol, a countermeasure may take the form of - a protocol feature, an element function, or a usage constraint. - - $ country code - (I) An identifier that is defined for a nation by ISO. [I3166] - - (C) For each nation, ISO Standard 3166 defines a unique two- - character alphabetic code, a unique three-character alphabetic - code, and a three-digit code. Among many uses of these codes, the - two-character codes are used as top-level domain names. - - $ covert channel - (I) A intra-system channel that permits two cooperating entities, - without exceeding their access authorizations, to transfer - information in a way that violates the system's security policy. - (See: channel, out of band.) - - (O) "A communications channel that allows two cooperating - processes to transfer information in a manner that violates the - system's security policy." [NCS04] - - (C) The cooperating entities can be either two insiders or an - insider and an outsider. Of course, an outsider has no access - authorization at all. A covert channel is a system feature that - the system architects neither designed nor intended for - information transfer: - - - "Timing channel": A system feature that enable one system - entity to signal information to another by modulating its own - use of a system resource in such a way as to affect system - response time observed by the second entity. - - - "Storage channel": A system feature that enables one system - entity to signal information to another entity by directly or - indirectly writing a storage location that is later directly or - indirectly read by the second entity. - - $ CPS - See: certification practice statement. - - $ cracker - (I) Someone who tries to break the security of, and gain access - to, someone else's system without being invited to do so. (See: - hacker and intruder.) - - $ CRAM - See: Challenge-Response Authentication Mechanism. - - - - -Shirey Informational [Page 46] - -RFC 2828 Internet Security Glossary May 2000 - - - $ CRC - See: cyclic redundancy check. - - $ credential(s) - (I) Data that is transferred or presented to establish either a - claimed identity or the authorizations of a system entity. (See: - authentication information, capability, ticket.) - - (O) "Data that is transferred to establish the claimed identity of - an entity." [I7498 Part 2] - - $ critical - 1. (I) "Critical" system resource: A condition of a service or - other system resource such that denial of access to (i.e., lack of - availability of) that resource would jeopardize a system user's - ability to perform a primary function or would result in other - serious consequences. (See: availability, sensitive.) - - 2. (N) "Critical" extension: Each extension of an X.509 - certificate (or CRL) is marked as being either critical or non- - critical. If an extension is critical and a certificate user (or - CRL user) does not recognize the extension type or does not - implement its semantics, then the user is required to treat the - certificate (or CRL) as invalid. If an extension is non-critical, - a user that does not recognize or implement that extension type is - permitted to ignore the extension and process the rest of the - certificate (or CRL). - - $ CRL - See: certificate revocation list. - - $ CRL distribution point - See: distribution point. - - $ CRL extension - See: extension. - - $ cross-certificate - See: cross-certification. - - $ cross-certification - (I) The act or process by which two CAs each certify a public key - of the other, issuing a public-key certificate to that other CA. - - (C) Cross-certification enables users to validate each other's - certificate when the users are certified under different - certification hierarchies. - - - - -Shirey Informational [Page 47] - -RFC 2828 Internet Security Glossary May 2000 - - - $ cryptanalysis - (I) The mathematical science that deals with analysis of a - cryptographic system in order to gain knowledge needed to break or - circumvent the protection that the system is designed to provide. - (See: cryptology.) - - (O) "The analysis of a cryptographic system and/or its inputs and - outputs to derive confidential variables and/or sensitive data - including cleartext." [I7498 Part 2] - - (C) The "O" definition states the traditional goal of - cryptanalysis--convert the ciphertext to plaintext (which usually - is cleartext) without knowing the key--but that definition applies - only to encryption systems. Today, the term is used with reference - to all kinds of cryptographic algorithms and key management, and - the "I" definition reflects that. In all cases, however, a - cryptanalyst tries to uncover or reproduce someone else's - sensitive data, such as cleartext, a key, or an algorithm. The - basic cryptanalytic attacks on encryption systems are ciphertext- - only, known-plaintext, chosen-plaintext, and chosen-ciphertext; - and these generalize to the other kinds of cryptography. - - $ crypto - (D) Except as part of certain long-established terms listed in - this Glossary, ISDs SHOULD NOT use this abbreviated term because - it may be misunderstood. Instead, use "cryptography" or - "cryptographic". - - $ cryptographic algorithm - (I) An algorithm that employs the science of cryptography, - including encryption algorithms, cryptographic hash algorithms, - digital signature algorithms, and key agreement algorithms. - - $ cryptographic application programming interface (CAPI) - (I) The source code formats and procedures through which an - application program accesses cryptographic services, which are - defined abstractly compared to their actual implementation. For - example, see: PKCS #11, [R2628]. - - $ cryptographic card - (I) A cryptographic token in the form of a smart card or a PC - card. - - $ cryptographic component - (I) A generic term for any system component that involves - cryptography. (See: cryptographic module.) - - - - - -Shirey Informational [Page 48] - -RFC 2828 Internet Security Glossary May 2000 - - - $ cryptographic hash - See: (secondary definition under) hash function. - - $ cryptographic ignition key (CIK) - (I) A physical (usually electronic) token used to store, - transport, and protect cryptographic keys. (Sometimes abbreviated - as "crypto ignition key".) - - (C) A typical use is to divide a split key between a CIK and a - cryptographic module, so that it is necessary to combine the two - to regenerate a key-encrypting key and thus activate the module - and other keys it contains. - - $ cryptographic key - (I) Usually shortened to just "key". An input parameter that - varies the transformation performed by a cryptographic algorithm. - - (O) "A sequence of symbols that controls the operations of - encipherment and decipherment." [I7498 Part 2] - - (C) If a key value needs to be kept secret, the sequence of - symbols (usually bits) that comprise it should be random, or at - least pseudo-random, because that makes the key hard for an - adversary to guess. (See: cryptanalysis, brute force attack.) - - $ Cryptographic Message Syntax (CMS) - (I) A encapsulation syntax for digital signatures, hashes, and - encryption of arbitrary messages. [R2630] - - (C) CMS was derived from PKCS #7. CMS values are specified with - ASN.1 and use BER encoding. The syntax permits multiple - encapsulation with nesting, permits arbitrary attributes to be - signed along with message content, and supports a variety of - architectures for digital certificate-based key management. - - $ cryptographic module - (I) A set of hardware, software, firmware, or some combination - thereof that implements cryptographic logic or processes, - including cryptographic algorithms, and is contained within the - module's cryptographic boundary, which is an explicitly defined - contiguous perimeter that establishes the physical bounds of the - module. [FP140] - - $ cryptographic system - (I) A set of cryptographic algorithms together with the key - management processes that support use of the algorithms in some - application context. - - - - -Shirey Informational [Page 49] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) This "I" definition covers a wider range of algorithms than - the following "O" definition: - - (O) "A collection of transformations from plaintext into - ciphertext and vice versa [which would exclude digital signature, - cryptographic hash, and key agreement algorithms], the particular - transformation(s) to be used being selected by keys. The - transformations are normally defined by a mathematical algorithm." - [X509] - - $ cryptographic token - (I) A portable, user-controlled, physical device used to store - cryptographic information and possibly perform cryptographic - functions. (See: cryptographic card, token.) - - (C) A smart token may implement some set of cryptographic - algorithms and may implement related algorithms and key management - functions, such as a random number generator. A smart - cryptographic token may contain a cryptographic module or may not - be explicitly designed that way. - - $ cryptography - (I) The mathematical science that deals with transforming data to - render its meaning unintelligible (i.e., to hide its semantic - content), prevent its undetected alteration, or prevent its - unauthorized use. If the transformation is reversible, - cryptography also deals with restoring encrypted data to - intelligible form. (See: cryptology, steganography.) - - (O) "The discipline which embodies principles, means, and methods - for the transformation of data in order to hide its information - content, prevent its undetected modification and/or prevent its - unauthorized use. . . . Cryptography determines the methods used - in encipherment and decipherment." [I7498 Part 2] - - $ Cryptoki - See: (secondary definition under) PKCS #11. - - $ cryptology - (I) The science that includes both cryptography and cryptanalysis, - and sometimes is said to include steganography. - - $ cryptonet - (I) A group of system entities that share a secret cryptographic - key for a symmetric algorithm. - - - - - - -Shirey Informational [Page 50] - -RFC 2828 Internet Security Glossary May 2000 - - - $ cryptoperiod - (I) The time span during which a particular key is authorized to - be used in a cryptographic system. (See: key management.) - - (C) A cryptoperiod is usually stated in terms of calendar or clock - time, but sometimes is stated in terms of the maximum amount of - data permitted to be processed by a cryptographic algorithm using - the key. Specifying a cryptoperiod involves a tradeoff between the - cost of rekeying and the risk of successful cryptanalysis. - - (C) Although we deprecate its prefix, this term is long- - established in COMPUSEC usage. (See: crypto) In the context of - certificates and public keys, "key lifetime" and "validity period" - are often used instead. - - $ cryptosystem - (D) ISDs SHOULD NOT use this term as an abbreviation for - cryptographic system. (For rationale, see: crypto.) - - $ CSIRT - See: computer security incident response team. - - $ CSOR - See: Computer Security Objects Register. - - $ cut-and-paste attack - (I) An active attack on the data integrity of ciphertext, effected - by replacing sections of ciphertext with other ciphertext, such - that the result appears to decrypt correctly but actually decrypts - to plaintext that is forged to the satisfaction of the attacker. - - $ cyclic redundancy check (CRC) - (I) Sometimes called "cyclic redundancy code". A type of checksum - algorithm that is not a cryptographic hash but is used to - implement data integrity service where accidental changes to data - are expected. - - $ DAC - See: Data Authentication Code, discretionary access control. - - $ DASS - See: Distributed Authentication Security Service. - - $ data - (I) Information in a specific physical representation, usually a - sequence of symbols that have meaning; especially a representation - of information that can be processed or produced by a computer. - - - - -Shirey Informational [Page 51] - -RFC 2828 Internet Security Glossary May 2000 - - - $ Data Authentication Algorithm - (N) A keyed hash function equivalent to DES cipher block chaining - with IV = 0. [A9009] - - (D) ISDs SHOULD NOT use the uncapitalized form of this term as a - synonym for other kinds of checksums. - - $ data authentication code vs. Data Authentication Code (DAC) - 1. (N) Capitalized: "The Data Authentication Code" refers to a - U.S. Government standard [FP113] for a checksum that is computed - by the Data Authentication Algorithm. (Also known as the ANSI - standard Message Authentication Code [A9009].) - - 2. (D) Not capitalized: ISDs SHOULD NOT use "data authentication - code" as a synonym for another kind of checksum, because this term - mixes concepts in a potentially misleading way. (See: - authentication code.) Instead, use "checksum", "error detection - code", "hash", "keyed hash", "Message Authentication Code", or - "protected checksum", depending on what is meant. - - $ data compromise - (I) A security incident in which information is exposed to - potential unauthorized access, such that unauthorized disclosure, - alteration, or use of the information may have occurred. (See: - compromise.) - - $ data confidentiality - (I) "The property that information is not made available or - disclosed to unauthorized individuals, entities, or processes - [i.e., to any unauthorized system entity]." [I7498 Part 2]. (See: - data confidentiality service.) - - (D) ISDs SHOULD NOT use this term as a synonym for "privacy", - which is a different concept. - - $ data confidentiality service - (I) A security service that protects data against unauthorized - disclosure. (See: data confidentiality.) - - (D) ISDs SHOULD NOT use this term as a synonym for "privacy", - which is a different concept. - - $ Data Encryption Algorithm (DEA) - (N) A symmetric block cipher, defined as part of the U.S. - Government's Data Encryption Standard. DEA uses a 64-bit key, of - which 56 bits are independently chosen and 8 are parity bits, and - maps a 64-bit block into another 64-bit block. [FP046] (See: DES, - symmetric cryptography.) - - - -Shirey Informational [Page 52] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) This algorithm is usually referred to as "DES". The algorithm - has also been adopted in standards outside the Government (e.g., - [A3092]). - - $ data encryption key (DEK) - (I) A cryptographic key that is used to encipher application data. - (See: key-encrypting key.) - - $ Data Encryption Standard (DES) - (N) A U.S. Government standard [FP046] that specifies the Data - Encryption Algorithm and states policy for using the algorithm to - protect unclassified, sensitive data. (See: AES, DEA.) - - $ data integrity - (I) The property that data has not been changed, destroyed, or - lost in an unauthorized or accidental manner. (See: data integrity - service.) - - (O) "The property that information has not been modified or - destroyed in an unauthorized manner." [I7498 Part 2] - - (C) Deals with constancy of and confidence in data values, not - with the information that the values represent (see: correctness - integrity) or the trustworthiness of the source of the values - (see: source integrity). - - $ data integrity service - (I) A security service that protects against unauthorized changes - to data, including both intentional change or destruction and - accidental change or loss, by ensuring that changes to data are - detectable. (See: data integrity.) - - (C) A data integrity service can only detect a change and report - it to an appropriate system entity; changes cannot be prevented - unless the system is perfect (error-free) and no malicious user - has access. However, a system that offers data integrity service - might also attempt to correct and recover from changes. - - (C) Relationship between data integrity service and authentication - services: Although data integrity service is defined separately - from data origin authentication service and peer entity - authentication service, it is closely related to them. - Authentication services depend, by definition, on companion data - integrity services. Data origin authentication service provides - verification that the identity of the original source of a - received data unit is as claimed; there can be no such - verification if the data unit has been altered. Peer entity - - - - -Shirey Informational [Page 53] - -RFC 2828 Internet Security Glossary May 2000 - - - authentication service provides verification that the identity of - a peer entity in a current association is as claimed; there can be - no such verification if the claimed identity has been altered. - - $ data origin authentication - (I) "The corroboration that the source of data received is as - claimed." [I7498 Part 2] (See: authentication.) - - $ data origin authentication service - (I) A security service that verifies the identity of a system - entity that is claimed to be the original source of received data. - (See: authentication, authentication service.) - - (C) This service is provided to any system entity that receives or - holds the data. Unlike peer entity authentication service, this - service is independent of any association between the originator - and the recipient, and the data in question may have originated at - any time in the past. - - (C) A digital signature mechanism can be used to provide this - service, because someone who does not know the private key cannot - forge the correct signature. However, by using the signer's public - key, anyone can verify the origin of correctly signed data. - - (C) This service is usually bundled with connectionless data - integrity service. (See: (relationship between data integrity - service and authentication services under) data integrity service. - - $ data privacy - (D) ISDs SHOULD NOT use this term because it mix concepts in a - potentially misleading way. Instead, use either "data - confidentiality" or "privacy", depending on what is meant. - - $ data security - (I) The protection of data from disclosure, alteration, - destruction, or loss that either is accidental or is intentional - but unauthorized. - - (C) Both data confidentiality service and data integrity service - are needed to achieve data security. - - $ datagram - (I) "A self-contained, independent entity of data carrying - sufficient information to be routed from the source to the - destination." [R1983] - - $ DEA - See: Data Encryption Algorithm. - - - -Shirey Informational [Page 54] - -RFC 2828 Internet Security Glossary May 2000 - - - $ deception - See: (secondary definition under) threat consequence. - - $ decipher - (D) ISDs SHOULD NOT use this term as a synonym for "decrypt", - except in special circumstances. (See: (usage discussion under) - encryption.) - - $ decipherment - (D) ISDs SHOULD NOT use this term as a synonym for "decryption", - except in special circumstances. (See: (usage discussion under) - encryption.) - - $ decode - (I) Convert encoded data back to its original form of - representation. (See: decrypt.) - - (D) ISDs SHOULD NOT use this term as a synonym for "decrypt", - because that would mix concepts in a potentially misleading way. - - $ decrypt - (I) Cryptographically restore ciphertext to the plaintext form it - had before encryption. - - $ decryption - See: (secondary definition under) encryption. - - $ dedicated security mode - (I) A mode of operation of an information system, wherein all - users have the clearance or authorization, and the need-to-know, - for all data handled by the system. In this mode, the system may - handle either a single classification level or category of - information or a range of levels and categories. [DOD2] - - (C) This mode is defined formally in U.S. Department of Defense - policy regarding system accreditation, but the term is also used - outside the Defense Department and outside the Government. - - $ default account - (I) A system login account (usually accessed with a user name and - password) that has been predefined in a manufactured system to - permit initial access when the system is first put into service. - - (C) Sometimes, the default user name and password are the same in - each copy of the system. In any case, when the system is put into - service, the default password should immediately be changed or the - default account should be disabled. - - - - -Shirey Informational [Page 55] - -RFC 2828 Internet Security Glossary May 2000 - - - $ degauss - (N) Apply a magnetic field to permanently remove, erase, or clear - data from a magnetic storage medium, such as a tape or disk - [NCS25]. Reduce magnetic flux density to zero by applying a - reversing magnetic field. - - $ degausser - (N) An electrical device that can degauss magnetic storage media. - - $ DEK - See: data encryption key. - - $ delta CRL - (I) A partial CRL that only contains entries for X.509 - certificates that have been revoked since the issuance of a prior, - base CRL. This method can be used to partition CRLs that become - too large and unwieldy. - - $ denial of service - (I) The prevention of authorized access to a system resource or - the delaying of system operations and functions. (See: - availability, critical (resource of a system), flooding.) - - $ DES - See: Data Encryption Standard. - - $ dictionary attack - (I) An attack that uses a brute-force technique of successively - trying all the words in some large, exhaustive list. - - (C) For example, an attack on an authentication service by trying - all possible passwords; or an attack on encryption by encrypting - some known plaintext phrase with all possible keys so that the key - for any given encrypted message containing that phrase may be - obtained by lookup. - - $ Diffie-Hellman - (N) A key agreement algorithm published in 1976 by Whitfield - Diffie and Martin Hellman [DH76, R2631]. - - (C) Diffie-Hellman does key establishment, not encryption. - However, the key that it produces may be used for encryption, for - further key management operations, or for any other cryptography. - - (C) The difficulty of breaking Diffie-Hellman is considered to be - equal to the difficulty of computing discrete logarithms modulo a - large prime. The algorithm is described in [R2631] and [Schn]. In - brief, Alice and Bob together pick large integers that satisfy - - - -Shirey Informational [Page 56] - -RFC 2828 Internet Security Glossary May 2000 - - - certain mathematical conditions, and then use the integers to each - separately compute a public-private key pair. They send each other - their public key. Each person uses their own private key and the - other person's public key to compute a key, k, that, because of - the mathematics of the algorithm, is the same for each of them. - Passive wiretapping cannot learn the shared k, because k is not - transmitted, and neither are the private keys needed to compute k. - However, without additional mechanisms to authenticate each party - to the other, a protocol based on the algorithm may be vulnerable - to a man-in-the-middle attack. - - $ digest - See: message digest. - - $ digital certificate - (I) A certificate document in the form of a digital data object (a - data object used by a computer) to which is appended a computed - digital signature value that depends on the data object. (See: - attribute certificate, capability, public-key certificate.) - - (D) ISDs SHOULD NOT use this term to refer to a signed CRL or CKL. - Although the recommended definition can be interpreted to include - those items, the security community does not use the term with - those meanings. - - $ digital certification - (D) ISDs SHOULD NOT use this term as a synonym for - "certification", unless the context is not sufficient to - distinguish between digital certification and another kind of - certification, in which case it would be better to use "public-key - certification" or another phrase that indicates what is being - certified. - - $ digital document - (I) An electronic data object that represents information - originally written in a non-electronic, non-magnetic medium - (usually ink on paper) or is an analogue of a document of that - type. - - $ digital envelope - (I) A digital envelope for a recipient is a combination of (a) - encrypted content data (of any kind) and (b) the content - encryption key in an encrypted form that has been prepared for the - use of the recipient. - - (C) In ISDs, this term should be defined at the point of first use - because, although the term is defined in PKCS #7 and used in - S/MIME, it is not yet widely established. - - - -Shirey Informational [Page 57] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) Digital enveloping is not simply a synonym for implementing - data confidentiality with encryption; digital enveloping is a - hybrid encryption scheme to "seal" a message or other data, by - encrypting the data and sending both it and a protected form of - the key to the intended recipient, so that no one other than the - intended recipient can "open" the message. In PCKS #7, it means - first encrypting the data using a symmetric encryption algorithm - and a secret key, and then encrypting the secret key using an - asymmetric encryption algorithm and the public key of the intended - recipient. In S/MIME, additional methods are defined for - conveying the content encryption key. - - $ Digital ID(service mark) - (D) ISDs SHOULD NOT use this term as a synonym for "digital - certificate" because (a) it is the service mark of a commercial - firm, (b) it unnecessarily duplicates the meaning of other, well- - established terms, and (c) a certificate is not always used as - authentication information. In some contexts, however, it may be - useful to explain that the key conveyed in a public-key - certificate can be used to verify an identity and, therefore, that - the certificate can be thought of as digital identification - information. (See: identification information.) - - $ digital key - (C) The adjective "digital" need not be used with "key" or - "cryptographic key", unless the context is insufficient to - distinguish the digital key from another kind of key, such as a - metal key for a door lock. - - $ digital notary - (I) Analogous to a notary public. Provides a trusted date-and-time - stamp for a document, so that someone can later prove that the - document existed at a point in time. May also verify the - signature(s) on a signed document before applying the stamp. (See: - notarization.) - - $ digital signature - (I) A value computed with a cryptographic algorithm and appended - to a data object in such a way that any recipient of the data can - use the signature to verify the data's origin and integrity. (See: - data origin authentication service, data integrity service, - digitized signature, electronic signature, signer.) - - (I) "Data appended to, or a cryptographic transformation of, a - data unit that allows a recipient of the data unit to prove the - source and integrity of the data unit and protect against forgery, - e.g. by the recipient." [I7498 Part 2] - - - - -Shirey Informational [Page 58] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) Typically, the data object is first input to a hash function, - and then the hash result is cryptographically transformed using a - private key of the signer. The final resulting value is called the - digital signature of the data object. The signature value is a - protected checksum, because the properties of a cryptographic hash - ensure that if the data object is changed, the digital signature - will no longer match it. The digital signature is unforgeable - because one cannot be certain of correctly creating or changing - the signature without knowing the private key of the supposed - signer. - - (C) Some digital signature schemes use a asymmetric encryption - algorithm (e.g., see: RSA) to transform the hash result. Thus, - when Alice needs to sign a message to send to Bob, she can use her - private key to encrypt the hash result. Bob receives both the - message and the digital signature. Bob can use Alice's public key - to decrypt the signature, and then compare the plaintext result to - the hash result that he computes by hashing the message himself. - If the values are equal, Bob accepts the message because he is - certain that it is from Alice and has arrived unchanged. If the - values are not equal, Bob rejects the message because either the - message or the signature was altered in transit. - - (C) Other digital signature schemes (e.g., see: DSS) transform the - hash result with an algorithm (e.g., see: DSA, El Gamal) that - cannot be directly used to encrypt data. Such a scheme creates a - signature value from the hash and provides a way to verify the - signature value, but does not provide a way to recover the hash - result from the signature value. In some countries, such a scheme - may improve exportability and avoid other legal constraints on - usage. - - $ Digital Signature Algorithm (DSA) - (N) An asymmetric cryptographic algorithm that produces a digital - signature in the form of a pair of large numbers. The signature is - computed using rules and parameters such that the identity of the - signer and the integrity of the signed data can be verified. (See: - Digital Signature Standard.) - - $ Digital Signature Standard (DSS) - (N) The U.S. Government standard [FP186] that specifies the - Digital Signature Algorithm (DSA), which involves asymmetric - cryptography. - - $ digital watermarking - (I) Computing techniques for inseparably embedding unobtrusive - marks or labels as bits in digital data--text, graphics, images, - video, or audio--and for detecting or extracting the marks later. - - - -Shirey Informational [Page 59] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) The set of embedded bits (the digital watermark) is sometimes - hidden, usually imperceptible, and always intended to be - unobtrusive. Depending on the particular technique that is used, - digital watermarking can assist in proving ownership, controlling - duplication, tracing distribution, ensuring data integrity, and - performing other functions to protect intellectual property - rights. [ACM] - - $ digitized signature - (D) ISDs SHOULD NOT use this term because there is no current - consensus on its definition. Although it appears to be used mainly - to refer to various forms of digitized images of handwritten - signatures, the term should be avoided because it might be - confused with "digital signature". - - $ directory - $ Directory - See: directory vs. Directory. - - $ Directory Access Protocol (DAP) - (N) An OSI protocol [X519] for communication between a Directory - User Agent (a client) and a Directory System Agent (a server). - (See: Lightweight Directory Access Protocol.) - - $ directory vs. Directory - 1. (I) Not capitalized: The term "directory" refers generically to - a database server or other system that provides information--such - as a digital certificate or CRL--about an entity whose name is - known. - - 2. (I) Capitalized: "Directory" refers specifically to the X.500 - Directory. (See: repository.) - - $ disaster plan - (D) A synonym for "contingency plan". In the interest of - consistency, ISDs SHOULD use "contingency plan" instead of - "disaster plan". - - $ disclosure (i.e., unauthorized disclosure) - See: (secondary definition under) threat consequence. - - $ discretionary access control (DAC) - (I) An access control service that enforces a security policy - based on the identity of system entities and their authorizations - to access system resources. (See: access control list, identity- - based security policy, mandatory access control.) - - - - - -Shirey Informational [Page 60] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) This service is termed "discretionary" because an entity might - have access rights that permit the entity, by its own volition, to - enable another entity to access some resource. - - (O) "A means of restricting access to objects based on the - identity of subjects and/or groups to which they belong. The - controls are discretionary in the sense that a subject with a - certain access permission is capable of passing that permission - (perhaps indirectly) on to any other subject." [DOD1] - - $ disruption - See: (secondary definition under) threat consequence. - - $ Distinguished Encoding Rules (DER) - (N) A subset of the Basic Encoding Rules, which gives exactly one - way to represent any ASN.1 value as an octet string [X690]. - - (C) Since there is more than one way to encode ASN.1 in BER, DER - is used in applications in which a unique encoding is needed, such - as when a digital signature is computed on an ASN.1 value. - - $ distinguished name (DN) - (I) An identifier that uniquely represents an object in the X.500 - Directory Information Tree (DIT) [X501]. (See: domain name.) - - (C) A DN is a set of attribute values that identify the path - leading from the base of the DIT to the object that is named. An - X.509 public-key certificate or CRL contains a DN that identifies - its issuer, and an X.509 attribute certificate contains a DN or - other form of name that identifies its subject. - - $ Distributed Authentication Security Service (DASS) - (I) An experimental Internet protocol [R1507] that uses - cryptographic mechanisms to provide strong, mutual authentication - services in a distributed environment. - - $ distribution point - (I) An X.500 Directory entry or other information source that is - named in a v3 X.509 public-key certificate extension as a location - from which to obtain a CRL that might list the certificate. - - (C) A v3 X.509 public-key certificate may have a - "cRLDistributionPoints" extension that names places to get CRLs on - which the certificate might be listed. A CRL obtained from a - distribution point may (a) cover either all reasons for which a - certificate might be revoked or only some of the reasons, (b) be - issued by either the authority that signed the certificate or some - - - - -Shirey Informational [Page 61] - -RFC 2828 Internet Security Glossary May 2000 - - - other authority, and (c) contain revocation entries for only a - subset of the full set of certificates issued by one CA or (c') - contain revocation entries for multiple CAs. - - $ DN - See: distinguished name. - - $ DNS - See: Domain Name System. - - $ DOI - See: Domain of Interpretation. - - $ domain - (I) Security usage: An environment or context that is defined by a - security policy, security model, or security architecture to - include a set of system resources and the set of system entities - that have the right to access the resources. (See: domain of - interpretation, security perimeter.) - - (I) Internet usage: That part of the Internet domain name space - tree [R1034] that is at or below the name the specifies the - domain. A domain is a subdomain of another domain if it is - contained within that domain. For example, D.C.B.A is a subdomain - of C.B.A. (See: Domain Name System.) - - (O) MISSI usage: The domain of a MISSI CA is the set of MISSI - users whose certificates are signed by the CA. - - (O) OSI usage: An administrative partition of a complex - distributed OSI system. - - $ domain name - (I) The style of identifier--a sequence of case-insensitive ASCII - labels separated by dots ("bbn.com.")--defined for subtrees in the - Internet Domain Name System [R1034] and used in other Internet - identifiers, such as host names (e.g., "rosslyn.bbn.com."), - mailbox names (e.g., "rshirey@bbn.com."), and URLs (e.g., - "http://www.rosslyn.bbn.com/foo"). (See: distinguished name, - domain.) - - (C) The domain name space of the DNS is a tree structure in which - each node and leaf holds records describing a resource. Each node - has a label. The domain name of a node is the list of labels on - the path from the node to the root of the tree. The labels in a - domain name are printed or read left to right, from the most - specific (lowest, farthest from the root) to the least specific - (highest, closest to the root). The root's label is the null - - - -Shirey Informational [Page 62] - -RFC 2828 Internet Security Glossary May 2000 - - - string, so a complete domain name properly ends in a dot. The top- - level domains, those immediately below the root, include COM, EDU, - GOV, INT, MIL, NET, ORG, and two-letter country codes (such as US) - from ISO-3166. [R1591] (See: country code.) - - $ Domain Name System (DNS) - (I) The main Internet operations database, which is distributed - over a collection of servers and used by client software for - purposes such as translating a domain name-style host name into an - IP address (e.g., "rosslyn.bbn.com" is "192.1.7.10") and locating - a host that accepts mail for some mailbox address. [R1034] - - (C) The DNS has three major components: - - - Domain name space and resource records: Specifications for the - tree-structured domain name space, and data associated with the - names. - - - Name servers: Programs that hold information about a subset of - the tree's structure and data holdings, and also hold pointers - to other name servers that can provide information from any - part of the tree. - - - Resolvers: Programs that extract information from name servers - in response to client requests; typically, system routines - directly accessible to user programs. - - (C) Extensions to the DNS [R2065, R2137, R2536] support (a) key - distribution for public keys needed for the DNS and for other - protocols, (b) data origin authentication service and data - integrity service for resource records, (c) data origin - authentication service for transactions between resolvers and - servers, and (d) access control of records. - - $ domain of interpretation (DOI) - (I) IPsec usage: An ISAKMP/IKE DOI defines payload formats, - exchange types, and conventions for naming security-relevant - information such as security policies or cryptographic algorithms - and modes. - - (C) For example, see [R2407]. The DOI concept is based on work by - the TSIG's CIPSO Working Group. - - $ dominate - (I) Security level A is said to "dominate" security level B if the - hierarchical classification level of A is greater (higher) than or - equal to that of B and the nonhierarchical categories of A include - all of those of B. - - - -Shirey Informational [Page 63] - -RFC 2828 Internet Security Glossary May 2000 - - - $ dongle - (I) A portable, physical, electronic device that is required to be - attached to a computer to enable a particular software program to - run. (See: token.) - - (C) A dongle is essentially a physical key used for copy - protection of software, because the program will not run unless - the matching dongle is attached. When the software runs, it - periodically queries the dongle and quits if the dongle does not - reply with the proper authentication information. Dongles were - originally constructed as an EPROM (erasable programmable read- - only memory) to be connected to a serial input-output port of a - personal computer. - - $ downgrade - (I) Reduce the classification level of information in an - authorized manner. - - $ draft RFC - (D) ISDs SHOULD NOT use this term, because the Request for Comment - series is archival in nature and does not have a "draft" category. - (Instead, see: Internet Draft, Draft Standard (in Internet - Standard).) - - $ DSA - See: Digital Signature Algorithm. - - $ DSS - See: Digital Signature Standard. - - $ dual control - (I) A procedure that uses two or more entities (usually persons) - operating in concert to protect a system resource, such that no - single entity acting alone can access that resource. (See: no-lone - zone, separation of duties, split knowledge.) - - $ dual signature - (D) ISDs SHOULD NOT use this term except when stated as - "SET(trademark) dual signature" with the following meaning: - - (O) SET usage: A single digital signature that protects two - separate messages by including the hash results for both sets in a - single encrypted value. [SET2] - - - - - - - - -Shirey Informational [Page 64] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) Generated by hashing each message separately, concatenating - the two hash results, and then hashing that value and encrypting - the result with the signer's private key. Done to reduce the - number of encryption operations and to enable verification of data - integrity without complete disclosure of the data. - - $ EAP - See: Extensible Authentication Protocol - - $ eavesdropping - (I) Passive wiretapping done secretly, i.e., without the knowledge - of the originator or the intended recipients of the communication. - - $ ECB - See: electronic codebook. - - $ ECDSA - See: Elliptic Curve Digital Signature Algorithm. - - $ economy of mechanism - (I) The principle that each security mechanism should be designed - to be as simple as possible, so that the mechanism can be - correctly implemented and so that it can be verified that the - operation of the mechanism enforces the containing system's - security policy. (See: least privilege.) - - $ EDI - See: electronic data interchange. - - $ EDIFACT - See: (secondary definition under) electronic data interchange. - - $ EE - (D) ISDs SHOULD NOT use this abbreviation because of possible - confusion among "end entity", "end-to-end encryption", "escrowed - encryption standard", and other terms. - - $ EES - See: Escrowed Encryption Standard. - - $ El Gamal algorithm - (N) An algorithm for asymmetric cryptography, invented in 1985 by - Taher El Gamal, that is based on the difficulty of calculating - discrete logarithms and can be used for both encryption and - digital signatures. [ElGa, Schn] - - - - - - -Shirey Informational [Page 65] - -RFC 2828 Internet Security Glossary May 2000 - - - $ electronic codebook (ECB) - (I) An block cipher mode in which a plaintext block is used - directly as input to the encryption algorithm and the resultant - output block is used directly as ciphertext [FP081]. - - $ electronic commerce - (I) General usage: Business conducted through paperless exchanges - of information, using electronic data interchange, electronic - funds transfer (EFT), electronic mail, computer bulletin boards, - facsimile, and other paperless technologies. - - (O) SET usage: "The exchange of goods and services for payment - between the cardholder and merchant when some or all of the - transaction is performed via electronic communication." [SET2] - - $ electronic data interchange (EDI) - (I) Computer-to-computer exchange, between trading partners, of - business data in standardized document formats. - - (C) EDI formats have been standardized primarily by ANSI X12 and - by EDIFACT (EDI for Administration, Commerce, and Transportation), - which is an international, UN-sponsored standard primarily used in - Europe and Asia. X12 and EDIFACT are aligning to create a single, - global EDI standard. - - $ electronic signature - (D) ISDs SHOULD NOT use this term because there is no current - consensus on its definition. (Instead, see: digital signature.) - - $ elliptic curve cryptography (ECC) - (I) A type of asymmetric cryptography based on mathematics of - groups that are defined by the points on a curve. - - (C) The most efficient implementation of ECC is claimed to be - stronger per bit of key (against cryptanalysis that uses a brute - force attack) than any other known form of asymmetric - cryptography. ECC is based on mathematics different than the kinds - originally used to define the Diffie-Hellman algorithm and the - Digital Signature Algorithm. ECC is based on the mathematics of - groups defined by the points on a curve, where the curve is - defined by a quadratic equation in a finite field. ECC can be used - to define both an algorithm for key agreement that is an analog of - Diffie-Hellman and an algorithm for digital signature that is an - analog of DSA. (See: ECDSA.) - - $ Elliptic Curve Digital Signature Algorithm (ECDSA) - (N) A standard [A9062] that is the elliptic curve cryptography - analog of the Digital Signature Algorithm. - - - -Shirey Informational [Page 66] - -RFC 2828 Internet Security Glossary May 2000 - - - $ emanation - (I) An signal (electromagnetic, acoustic, or other medium) that is - emitted by a system (through radiation or conductance) as a - consequence (i.e., byproduct) of its operation, and that may - contain information. (See: TEMPEST.) - - $ emanations security (EMSEC) - (I) Physical constraints to prevent information compromise through - signals emanated by a system, particular the application of - TEMPEST technology to block electromagnetic radiation. - - $ emergency plan - (D) A synonym for "contingency plan". In the interest of - consistency, ISDs SHOULD use "contingency plan" instead of - "emergency plan". - - $ EMSEC - See: emanations security. - - $ EMV - (I) An abbreviation of "Europay, MasterCard, Visa". Refers to a - specification for smart cards that are used as payment cards, and - for related terminals and applications. [EMV1, EMV2, EMV3] - - $ Encapsulating Security Payload (ESP) - (I) An Internet IPsec protocol [R2406] designed to provide a mix - of security services--especially data confidentiality service--in - the Internet Protocol. (See: Authentication Header.) - - (C) ESP may be used alone, or in combination with the IPsec AH - protocol, or in a nested fashion with tunneling. Security services - can be provided between a pair of communicating hosts, between a - pair of communicating security gateways, or between a host and a - gateway. The ESP header is encapsulated by the IP header, and the - ESP header encapsulates either the upper layer protocol header - (transport mode) or an IP header (tunnel mode). ESP can provide - data confidentiality service, data origin authentication service, - connectionless data integrity service, an anti-replay service, and - limited traffic flow confidentiality. The set of services depends - on the placement of the implementation and on options selected - when the security association is established. - - $ encipher - (D) ISDs SHOULD NOT use this term as a synonym for "encrypt". - However, see the usage note under "encryption". - - - - - - -Shirey Informational [Page 67] - -RFC 2828 Internet Security Glossary May 2000 - - - $ encipherment - (D) ISDs SHOULD NOT use this term as a synonym for "encryption", - except in special circumstances that are explained in the usage - discussion under "encryption". - - $ encode - (I) Use a system of symbols to represent information, which might - originally have some other representation. (See: decode.) - - (C) Examples include Morse code, ASCII, and BER. - - (D) ISDs SHOULD NOT use this term as a synonym for "encrypt", - because encoding is not usually intended to conceal meaning. - - $ encrypt - (I) Cryptographically transform data to produce ciphertext. (See: - encryption.) - - $ encryption - (I) Cryptographic transformation of data (called "plaintext") into - a form (called "ciphertext") that conceals the data's original - meaning to prevent it from being known or used. If the - transformation is reversible, the corresponding reversal process - is called "decryption", which is a transformation that restores - encrypted data to its original state. (See: cryptography.) - - (C) Usage note: For this concept, ISDs should use the verb "to - encrypt" (and related variations: encryption, decrypt, and - decryption). However, because of cultural biases, some - international usage, particularly ISO and CCITT standards, avoids - "to encrypt" and instead uses the verb "to encipher" (and related - variations: encipherment, decipher, decipherment). - - (O) "The cryptographic transformation of data (see: cryptography) - to produce ciphertext." [I7498 Part 2] - - (C) Usually, the plaintext input to an encryption operation is - cleartext. But in some cases, the plaintext may be ciphertext that - was output from another encryption operation. (See: - superencryption.) - - (C) Encryption and decryption involve a mathematical algorithm for - transforming data. In addition to the data to be transformed, the - algorithm has one or more inputs that are control parameters: (a) - a key value that varies the transformation and, in some cases, (b) - an initialization value that establishes the starting state of the - algorithm. - - - - -Shirey Informational [Page 68] - -RFC 2828 Internet Security Glossary May 2000 - - - $ encryption certificate - (I) A public-key certificate that contains a public key that is - intended to be used for encrypting data, rather than for verifying - digital signatures or performing other cryptographic functions. - - C) A v3 X.509 public-key certificate may have a "keyUsage" - extension that indicates the purpose for which the certified - public key is intended. - - $ end entity - (I) A system entity that is the subject of a public-key - certificate and that is using, or is permitted and able to use, - the matching private key only for a purpose or purposes other than - signing a digital certificate; i.e., an entity that is not a CA. - - (D) "A certificate subject which uses its public [sic] key for - purposes other than signing certificates." [X509] - - (C) ISDs SHOULD NOT use the X.509 definition, because it is - misleading and incomplete. First, the X.509 definition should say - "private key" rather than "public key" because certificates are - not usefully signed with a public key. Second, the X.509 - definition is weak regarding whether an end entity may or may not - use the private key to sign a certificate, i.e., whether the - subject may be a CA. The intent of X.509's authors was that an end - entity certificate is not valid for use in verifying a signature - on an X.509 certificate or X.509 CRL. Thus, it would have been - better for the X.509 definition to have said "only for purposes - other than signing certificates". - - (C) Despite the problems in the X.509 definition, the term itself - is useful in describing applications of asymmetric cryptography. - The way the term is used in X.509 implies that it was meant to be - defined, as we have done here, relative to roles that an entity - (which is associated with an OSI end system) is playing or is - permitted to play in applications of asymmetric cryptography other - than the PKI that supports applications. - - (C) Whether a subject can play both CA and non-CA roles, with - either the same or different certificates, is a matter of policy. - (See: certification practice statement.) A v3 X.509 public-key - certificate may have a "basicConstraints" extension containing a - "cA" value that specifically "indicates whether or not the public - key may be used to verify certificate signatures". - - - - - - - -Shirey Informational [Page 69] - -RFC 2828 Internet Security Glossary May 2000 - - - $ end system - (I) An OSI term for a computer that implements all seven layers of - the OSIRM and may attach to a subnetwork. (In the context of the - Internet Protocol Suite, usually called a "host".) - - $ end-to-end encryption - (I) Continuous protection of data that flows between two points in - a network, provided by encrypting data when it leaves its source, - leaving it encrypted while it passes through any intermediate - computers (such as routers), and decrypting only when the data - arrives at the intended destination. (See: link encryption, - wiretapping.) - - (C) When two points are separated by multiple communication links - that are connected by one or more intermediate relays, end-to-end - encryption enables the source and destination systems to protect - their communications without depending on the intermediate systems - to provide the protection. - - $ end user - (I) General usage: A system entity, usually a human individual, - that makes use of system resources, primarily for application - purposes as opposed to system management purposes. - - (I) PKI usage: A synonym for "end entity"; but the term "end - entity" is preferred. - - $ entity - See: system entity. - - $ entrapment - (I) "The deliberate planting of apparent flaws in a system for the - purpose of detecting attempted penetrations or confusing an - intruder about which flaws to exploit." [FP039] (See: honey pot.) - - $ ephemeral key - (I) A public key or a private key that is relatively short-lived. - (See: session key.) - - $ error detection code - (I) A checksum designed to detect, but not correct, accidental - (i.e., unintentional) changes in data. - - $ Escrowed Encryption Standard (EES) - (N) A U.S. Government standard [FP185] that specifies use of a - symmetric encryption algorithm (SKIPJACK) and a Law Enforcement - - - - - -Shirey Informational [Page 70] - -RFC 2828 Internet Security Glossary May 2000 - - - Access Field (LEAF) creation method to implement part of a key - escrow system that provides for decryption of encrypted - telecommunications when interception is lawfully authorized. - - (C) Both SKIPJACK and the LEAF are to be implemented in equipment - used to encrypt and decrypt unclassified, sensitive - telecommunications data. - - $ ESP - See: Encapsulating Security Payload. - - $ Estelle - (N) A language (ISO 9074-1989) for formal specification of - computer network protocols. - - $ evaluated products list - (O) General usage: A list of information system equipment items - that have been evaluated against, and found to be compliant with, - a particular set of criteria. - - (O) U.S. Department of Defense usage: The Evaluated Products List - (http://www.radium.ncsc.mil/tpep/epl/) contains items that have - been evaluated against the TCSEC by the NCSC, or against the - Common Criteria by the NCSC or one of its partner agencies in - another county. The List forms Chapter 4 of NSA's "Information - Systems Security Products and Services Catalogue". - - $ evaluated system - (I) Refers to a system that has been evaluated against security - criteria such as the TCSEC or the Common Criteria. - - $ expire - See: certificate expiration. - - $ exposure - See: (secondary definition under) threat consequence. - - $ Extensible Authentication Protocol - (I) A framework that supports multiple, optional authentication - mechanisms for PPP, including cleartext passwords, challenge- - response, and arbitrary dialog sequences. [R2284] - - (C) This protocol is intended for use primarily by a host or - router that connects to a PPP network server via switched circuits - or dial-up lines. - - - - - - -Shirey Informational [Page 71] - -RFC 2828 Internet Security Glossary May 2000 - - - $ extension - (I) A data item defined for optional inclusion in a v3 X.509 - public-key certificate or a v2 X.509 CRL. - - (C) The formats defined in X.509 can be extended to provide - methods for associating additional attributes with subjects and - public keys and for managing a certification hierarchy: - - - "Certificate extension": X.509 defines standard extensions that - may be included in v3 certificates to provide additional key - and security policy information, subject and issuer attributes, - and certification path constraints. - - - "CRL extension": X.509 defines extensions that may be included - in v2 CRLs to provide additional issuer key and name - information, revocation reasons and constraints, and - information about distribution points and delta CRLs. - - - "Private extension": Additional extensions, each named by an - OID, can be locally defined as needed by applications or - communities. (See: PKIX private extension, SET private - extensions.) - - $ extranet - (I) A computer network that an organization uses to carry - application data traffic between the organization and its business - partners. (See: intranet.) - - (C) An extranet can be implemented securely, either on the - Internet or using Internet technology, by constructing the - extranet as a VPN. - - $ fail safe - (I) A mode of system termination that automatically leaves system - processes and components in a secure state when a failure occurs - or is detected in the system. - - $ fail soft - (I) Selective termination of affected non-essential system - functions and processes when a failure occurs or is detected in - the system. - - $ failure control - (I) A methodology used to provide fail-safe or fail-soft - termination and recovery of functions and processes when failures - are detected or occur in a system. [FP039] - - - - - -Shirey Informational [Page 72] - -RFC 2828 Internet Security Glossary May 2000 - - - $ Federal Information Processing Standards (FIPS) - (N) The Federal Information Processing Standards Publication (FIPS - PUB) series issued by the U.S. National Institute of Standards and - Technology as technical guidelines for U.S. Government - procurements of information processing system equipment and - services. [FP031, FP039, FP046, FP081, FP102, FP113, FP140, FP151, - FP180, FP185, FP186, FP188] - - (C) Issued under the provisions of section 111(d) of the Federal - Property and Administrative Services Act of 1949 as amended by the - Computer Security Act of 1987, Public Law 100-235. - - $ Federal Public-key Infrastructure (FPKI) - (N) A PKI being planned to establish facilities, specifications, - and policies needed by the U.S. Federal Government to use public- - key certificates for INFOSEC, COMSEC, and electronic commerce - involving unclassified but sensitive applications and interactions - between Federal agencies as well as with entities of other - branches of the Federal Government, state, and local governments, - business, and the public. [FPKI] - - $ Federal Standard 1027 - (N) An U.S. Government document defining emanation, anti-tamper, - security fault analysis, and manual key management criteria for - DES encryption devices, primary for OSI layer 2. Was renamed "FIPS - PUB 140" when responsibility for protecting unclassified, - sensitive information was transferred from NSA to NIST, and then - was superseded by FIPS PUB 140-1. - - $ File Transfer Protocol (FTP) - (I) A TCP-based, application-layer, Internet Standard protocol - [R0959] for moving data files from one computer to another. - - $ filtering router - (I) An internetwork router that selectively prevents the passage - of data packets according to a security policy. - - (C) A filtering router may be used as a firewall or part of a - firewall. A router usually receives a packet from a network and - decides where to forward it on a second network. A filtering - router does the same, but first decides whether the packet should - be forwarded at all, according to some security policy. The policy - is implemented by rules (packet filters) loaded into the router. - The rules mostly involve values of data packet control fields - (especially IP source and destination addresses and TCP port - numbers). [R2179] - - - - - -Shirey Informational [Page 73] - -RFC 2828 Internet Security Glossary May 2000 - - - $ financial institution - (N) "An establishment responsible for facilitating customer- - initiated transactions or transmission of funds for the extension - of credit or the custody, loan, exchange, or issuance of money." - [SET2] - - $ fingerprint - (I) A pattern of curves formed by the ridges on a fingertip. (See: - biometric authentication, thumbprint.) - - (D) ISDs SHOULD NOT use this term as a synonym for "hash result" - because it mixes concepts in a potentially misleading way. - - (D) ISDs SHOULD NOT use this term with the following PGP - definition, because the term and definition mix concepts in a - potentially misleading way and duplicate the meaning of "hash - result": - - (O) PGP usage: A hash result used to authenticate a public key - (key fingerprint) or other data. [PGP] - - $ FIPS - See: Federal Information Processing Standards. - - $ FIPS PUB 140-1 - (N) The U.S. Government standard [FP140] for security requirements - to be met by a cryptographic module used to protect unclassified - information in computer and communication systems. (See: Common - Criteria, FIPS, Federal Standard 1027.) - - (C) The standard specifies four increasing levels (from "Level 1" - to "Level 4") of requirements to cover a wide range of potential - applications and environments. The requirements address basic - design and documentation, module interfaces, authorized roles and - services, physical security, software security, operating system - security, key management, cryptographic algorithms, - electromagnetic interference and electromagnetic compatibility - (EMI/EMC), and self-testing. NIST and the Canadian Communication - Security Establishment jointly certify modules. - - $ firewall - (I) An internetwork gateway that restricts data communication - traffic to and from one of the connected networks (the one said to - be "inside" the firewall) and thus protects that network's system - resources against threats from the other network (the one that is - said to be "outside" the firewall). (See: guard, security - gateway.) - - - - -Shirey Informational [Page 74] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) A firewall typically protects a smaller, secure network (such - as a corporate LAN, or even just one host) from a larger network - (such as the Internet). The firewall is installed at the point - where the networks connect, and the firewall applies security - policy rules to control traffic that flows in and out of the - protected network. - - (C) A firewall is not always a single computer. For example, a - firewall may consist of a pair of filtering routers and one or - more proxy servers running on one or more bastion hosts, all - connected to a small, dedicated LAN between the two routers. The - external router blocks attacks that use IP to break security (IP - address spoofing, source routing, packet fragments), while proxy - servers block attacks that would exploit a vulnerability in a - higher layer protocol or service. The internal router blocks - traffic from leaving the protected network except through the - proxy servers. The difficult part is defining criteria by which - packets are denied passage through the firewall, because a - firewall not only needs to keep intruders out, but usually also - needs to let authorized users in and out. - - $ firmware - (I) Computer programs and data stored in hardware--typically in - read-only memory (ROM) or programmable read-only memory (PROM)-- - such that the programs and data cannot be dynamically written or - modified during execution of the programs. (See: hardware, - software.) - - $ FIRST - See: Forum of Incident Response and Security Teams. - - $ flaw hypothesis methodology - (I) An evaluation or attack technique in which specifications and - documentation for a system are analyzed to hypothesize flaws in - the system. The list of hypothetical flaws is prioritized on the - basis of the estimated probability that a flaw exists and, - assuming it does, on the ease of exploiting it and the extent of - control or compromise it would provide. The prioritized list is - used to direct a penetration test or attack against the system. - [NCS04] - - $ flooding - (I) An attack that attempts to cause a failure in (especially, in - the security of) a computer system or other data processing entity - by providing more input than the entity can process properly. - (See: denial of service.) - - - - - -Shirey Informational [Page 75] - -RFC 2828 Internet Security Glossary May 2000 - - - $ flow analysis - (I) An analysis performed on a nonprocedural formal system - specification that locates potential flows of information between - system variables. By assigning security levels to the variables, - the analysis can find some types of covert channels. - - $ flow control - (I) A procedure or technique to ensure that information transfers - within a system are not made from one security level to another - security level, and especially not from a higher level to a lower - level. (See: covert channel, simple security property, confinement - property.) - - $ formal specification - (I) A specification of hardware or software functionality in a - computer-readable language; usually a precise mathematical - description of the behavior of the system with the aim of - providing a correctness proof. - - $ formulary - (I) A technique for enabling a decision to grant or deny access to - be made dynamically at the time the access is attempted, rather - than earlier when an access control list or ticket is created. - - $ FORTEZZA(trademark) - (N) A registered trademark of NSA, used for a family of - interoperable security products that implement a NIST/NSA-approved - suite of cryptographic algorithms for digital signature, hash, - encryption, and key exchange. The products include a PC card that - contains a CAPSTONE chip, serial port modems, server boards, smart - cards, and software implementations. - - $ Forum of Incident Response and Security Teams (FIRST) - (N) An international consortium of CSIRTs that work together to - handle computer security incidents and promote preventive - activities. (See: CSIRT, security incident.) - - (C) FIRST was founded in 1990 and, as of September 1999, had - nearly 70 members spanning the globe. Its mission includes: - - - Provide members with technical information, tools, methods, - assistance, and guidance. - - Coordinate proactive liaison activities and analytical support. - - Encourage development of quality products and services. - - Improve national and international information security for - government, private industry, academia, and the individual. - - Enhance the image and status of the CSIRT community. - - - - -Shirey Informational [Page 76] - -RFC 2828 Internet Security Glossary May 2000 - - - $ forward secrecy - See: public-key forward secrecy. - - $ FPKI - See: Federal Public-Key Infrastructure. - - $ FTP - See: File Transfer Protocol. - - $ gateway - (I) A relay mechanism that attaches to two (or more) computer - networks that have similar functions but dissimilar - implementations and that enables host computers on one network to - communicate with hosts on the other; an intermediate system that - is the interface between two computer networks. (See: bridge, - firewall, guard, internetwork, proxy server, router, and - subnetwork.) - - (C) In theory, gateways are conceivable at any OSI layer. In - practice, they operate at OSI layer 3 (see: bridge, router) or - layer 7 (see: proxy server). When the two networks differ in the - protocol by which they offer service to hosts, the gateway may - translate one protocol into another or otherwise facilitate - interoperation of hosts (see: Internet Protocol). - - $ GCA - See: geopolitical certificate authority. - - $ GeneralizedTime - (N) The ASN.1 data type "GeneralizedTime" (specified in ISO 8601) - contains a calendar date (YYYYMMDD) and a time of day, which is - either (a) the local time, (b) the Coordinated Universal Time, or - (c) both the local time and an offset allowing Coordinated - Universal Time to be calculated. (See: Coordinated Universal Time, - UTCTime.) - - $ Generic Security Service Application Program Interface (GSS-API) - (I) An Internet Standard protocol [R2078] that specifies calling - conventions by which an application (typically another - communication protocol) can obtain authentication, integrity, and - confidentiality security services independently of the underlying - security mechanisms and technologies, thus allowing the - application source code to be ported to different environments. - - (C) "A GSS-API caller accepts tokens provided to it by its local - GSS-API implementation and transfers the tokens to a peer on a - remote system; that peer passes the received tokens to its local - - - - -Shirey Informational [Page 77] - -RFC 2828 Internet Security Glossary May 2000 - - - GSS-API implementation for processing. The security services - available through GSS-API in this fashion are implementable (and - have been implemented) over a range of underlying mechanisms based - on [symmetric] and [asymmetric cryptography]." [R2078] - - $ geopolitical certificate authority (GCA) - (O) SET usage: In a SET certification hierarchy, an optional level - that is certified by a BCA and that may certify cardholder CAs, - merchant CAs, and payment gateway CAs. Using GCAs enables a brand - to distribute responsibility for managing certificates to - geographic or political regions, so that brand policies can vary - between regions as needed. - - $ Green Book - (D) Except as an explanatory appositive, ISDs SHOULD NOT use this - term as a synonym for "Defense Password Management Guideline" - [CSC2]. Instead, use the full proper name of the document or, in - subsequent references, a conventional abbreviation. (See: Rainbow - Series.) - - (D) Usage note: To improve international comprehensibility of - Internet Standards and the Internet Standards Process, ISDs SHOULD - NOT use "cute" synonyms for document titles. No matter how popular - and clearly understood a nickname may be in one community, it is - likely to cause confusion in others. For example, several other - information system standards also are called "the Green Book". The - following are some examples: - - - Each volume of 1992 ITU-T (at that time, CCITT) standards. - - "PostScript Language Program Design", Adobe Systems, Addison- - Wesley, 1988. - - IEEE 1003.1 POSIX Operating Systems Interface. - - "Smalltalk-80: Bits of History, Words of Advice", Glenn - Krasner, Addison-Wesley, 1983. - - "X/Open Compatibility Guide". - - A particular CD-ROM format developed by Phillips. - - $ GRIP - (I) A contraction of "Guidelines and Recommendations for Security - Incident Processing", the name of the IETF working group that - seeks to facilitate consistent handling of security incidents in - the Internet community. (See: security incident.) - - (C) Guidelines to be produced by the WG will address technology - vendors, network service providers, and response teams in their - roles assisting organizations in resolving security incidents. - These relationships are functional and can exist within and across - organizational boundaries. - - - -Shirey Informational [Page 78] - -RFC 2828 Internet Security Glossary May 2000 - - - $ GSS-API - See: Generic Security Service Application Program Interface. - - $ guard - (I) A gateway that is interposed between two networks (or - computers, or other information systems) operating at different - security levels (one level is usually higher than the other) and - is trusted to mediate all information transfers between the two - levels, either to ensure that no sensitive information from the - first (higher) level is disclosed to the second (lower) level, or - to protect the integrity of data on the first (higher) level. - (See: firewall.) - - $ guest login - See: anonymous login. - - $ GULS - (I) Generic Upper Layer Security service element (ISO 11586), a - five-part standard for the exchange of security information and - security-transformation functions that protect confidentiality and - integrity of application data. - - $ hacker - (I) Someone with a strong interest in computers, who enjoys - learning about them and experimenting with them. (See: cracker.) - - (C) The recommended definition is the original meaning of the term - (circa 1960), which then had a neutral or positive connotation of - "someone who figures things out and makes something cool - happen". Today, the term is frequently misused, especially by - journalists, to have the pejorative meaning of cracker. - - $ handle - (I) (1.) Verb: Perform processing operations on data, such as - receive and transmit, collect and disseminate, create and delete, - store and retrieve, read and write, and compare. (2.) Noun: An on- - line pseudonym, particularly one used by a cracker; derived from - citizens band radio culture. - - $ hardware - (I) The material physical components of a computer system. (See: - firmware, software.) - - $ hardware token - See: token. - - - - - - -Shirey Informational [Page 79] - -RFC 2828 Internet Security Glossary May 2000 - - - $ hash code - (D) ISDs SHOULD NOT use this term (especially not as a synonym for - "hash result") because it mixes concepts in a potentially - misleading way. A hash result is not a "code" in any sense defined - by this glossary. (See: code, hash result, hash value, message - digest.) - - $ hash function - (I) An algorithm that computes a value based on a data object - (such as a message or file; usually variable-length; possibly very - large), thereby mapping the data object to a smaller data object - (the "hash result") which is usually a fixed-size value. (See: - checksum, keyed hash.) - - (O) "A (mathematical) function which maps values from a large - (possibly very large) domain into a smaller range. A 'good' hash - function is such that the results of applying the function to a - (large) set of values in the domain will be evenly distributed - (and apparently at random) over the range." [X509] - - (C) The kind of hash function needed for security applications is - called a "cryptographic hash function", an algorithm for which it - is computationally infeasible (because no attack is significantly - more efficient than brute force) to find either (a) a data object - that maps to a pre-specified hash result (the "one-way" property) - or (b) two data objects that map to the same hash result (the - "collision-free" property). (See: MD2, MD4, MD5, SHA-1.) - - (C) A cryptographic hash is "good" in the sense stated in the "O" - definition for hash function. Any change to an input data object - will, with high probability, result in a different hash result, so - that the result of a cryptographic hash makes a good checksum for - a data object. - - $ hash result - (I) The output of a hash function. (See: hash code, hash value.) - - (O) "The output produced by a hash function upon processing a - message" (where "message" is broadly defined as "a digital - representation of data"). [ABA] (The recommended definition is - compatible with this ABA definition, but we avoid the unusual - definition of "message".) - - $ hash value - (D) ISDs SHOULD NOT use this term (especially not as a synonym for - "hash result", the output of a hash function) because it might be - confused with "hashed value" (the input to a hash function). (See: - hash code, hash result, message digest.) - - - -Shirey Informational [Page 80] - -RFC 2828 Internet Security Glossary May 2000 - - - $ hierarchical PKI - (I) A PKI architecture based on a certification hierarchy. (See: - mesh PKI, trust-file PKI.) - - $ hierarchy management - (I) The process of generating configuration data and issuing - public-key certificates to build and operate a certification - hierarchy. - - $ hierarchy of trust - (D) ISDs SHOULD NOT use this term with regard to PKI, especially - not as a synonym for "certification hierarchy", because this term - mixes concepts in a potentially misleading way. (See: - certification hierarchy, trust, web of trust.) - - $ hijack attack - (I) A form of active wiretapping in which the attacker seizes - control of a previously established communication association. - (See: man-in-the-middle attack, pagejacking, piggyback attack.) - - $ HMAC - (I) A keyed hash [R2104] that can be based on any iterated - cryptographic hash (e.g., MD5 or SHA-1), so that the cryptographic - strength of HMAC depends on the properties of the selected - cryptographic hash. (See: [R2202, R2403, R2404].) - - (C) Assume that H is a generic cryptographic hash in which a - function is iterated on data blocks of length B bytes. L is the - length of the of hash result of H. K is a secret key of length L - <= K <= B. The values IPAD and OPAD are fixed strings used as - inner and outer padding and defined as follows: IPAD = the byte - 0x36 repeated B times, OPAD = the byte 0x5C repeated B times. HMAC - is computed by H(K XOR OPAD, H(K XOR IPAD, inputdata)). - - (C) The goals of HMAC are as follows: - - - To use available cryptographic hash functions without - modification, particularly functions that perform well in - software and for which software is freely and widely available. - - To preserve the original performance of the selected hash - without significant degradation. - - To use and handle keys in a simple way. - - To have a well-understood cryptographic analysis of the - strength of the mechanism based on reasonable assumptions about - the underlying hash function. - - To enable easy replacement of the hash function in case a - faster or stronger hash is found or required. - - - - -Shirey Informational [Page 81] - -RFC 2828 Internet Security Glossary May 2000 - - - $ honey pot - (I) A system (e.g., a web server) or a system resource (e.g., a - file on a server), that is designed to be attractive to potential - crackers and intruders, like honey is attractive to bears. (See: - entrapment.) - - (D) It is likely that other cultures have different metaphors for - this concept. To ensure international understanding, ISDs should - not use this term unless they also provide an explanation like - this one. (See: (usage note under) Green Book.) - - $ host - (I) General computer network usage: A computer that is attached to - a communication subnetwork or internetwork and can use services - provided by the network to exchange data with other attached - systems. (See: end system.) - - (I) Specific Internet Protocol Suite usage: A networked computer - that does not forward Internet Protocol packets that are not - addressed to the computer itself. (See: router.) - - (C) Derivation: As viewed by its users, a host "entertains" - guests, providing application layer services or access to other - computers attached to the network. However, even though some - traditional peripheral service devices, such as printers, can now - be independently connected to networks, they are not usually - called hosts. - - $ HTML - See: Hypertext Markup Language. - - $ HTTP - See: Hypertext Transfer Protocol. - - $ https - (I) When used in the first part of a URL (the part that precedes - the colon and specifies an access scheme or protocol), this term - specifies the use of HTTP enhanced by a security mechanism, which - is usually SSL. (See: S-HTTP.) - - $ hybrid encryption - (I) An application of cryptography that combines two or more - encryption algorithms, particularly a combination of symmetric and - asymmetric encryption. (E.g., see: digital envelope.) - - (C) Asymmetric algorithms require more computation than - equivalently strong symmetric ones. Thus, asymmetric encryption is - not normally used for data confidentiality except in distributing - - - -Shirey Informational [Page 82] - -RFC 2828 Internet Security Glossary May 2000 - - - symmetric keys in applications where the key data is usually short - (in terms of bits) compared to the data it protects. (E.g., see: - MSP, PEM, PGP.) - - $ hyperlink - (I) In hypertext or hypermedia, an information object (such as a - word, a phrase, or an image; usually highlighted by color or - underscoring) that points (indicates how to connect) to related - information that is located elsewhere and can be retrieved by - activating the link (e.g., by selecting the object with a mouse - pointer and then clicking). - - $ hypermedia - (I) A generalization of hypertext; any media that contain - hyperlinks that point to material in the same or another data - object. - - $ hypertext - (I) A computer document, or part of a document, that contains - hyperlinks to other documents; i.e., text that contains active - pointers to other text. Usually written in Hypertext Markup - Language and accessed using a web browser. (See: hypermedia.) - - $ Hypertext Markup Language (HTML) - (I) A platform-independent system of syntax and semantics for - adding characters to data files (particularly text files) to - represent the data's structure and to point to related data, thus - creating hypertext for use in the World Wide Web and other - applications. [R1866] - - $ Hypertext Transfer Protocol (HTTP) - (I) A TCP-based, application-layer, client-server, Internet - protocol [R2616] used to carry data requests and responses in the - World Wide Web. (See: hypertext.) - - $ IAB - See: Internet Architecture Board. - - $ IANA - See: Internet Assigned Numbers Authority. - - $ ICANN - See: Internet Corporation for Assigned Names and Numbers. - - $ ICMP - See: Internet Control Message Protocol. - - - - - -Shirey Informational [Page 83] - -RFC 2828 Internet Security Glossary May 2000 - - - $ ICMP flood - (I) A denial of service attack that sends a host more ICMP echo - request ("ping") packets than the protocol implementation can - handle. (See: flooding, smurf.) - - $ ICRL - See: indirect certificate revocation list. - - $ IDEA - See: International Data Encryption Algorithm. - - $ identification - (I) An act or process that presents an identifier to a system so - that the system can recognize a system entity and distinguish it - from other entities. (See: authentication.) - - $ Identification Protocol - (I) An client-server Internet protocol [R1413] for learning the - identity of a user of a particular TCP connection. - - (C) Given a TCP port number pair, the server returns a character - string that identifies the owner of that connection on the - server's system. The protocol is not intended for authorization or - access control. At best, it provides additional auditing - information with respect to TCP. - - $ identity-based security policy - (I) "A security policy based on the identities and/or attributes - of users, a group of users, or entities acting on behalf of the - users and the resources/objects being accessed." [I7498 Part 2] - (See: rule-based security policy.) - - $ IEEE - See: Institute of Electrical and Electronics Engineers, Inc. - - $ IEEE 802.10 - (N) An IEEE committee developing security standards for local area - networks. (See: SILS.) - - $ IEEE P1363 - (N) An IEEE working group, Standard for Public-Key Cryptography, - developing a comprehensive reference standard for asymmetric - cryptography. Covers discrete logarithm (e.g., DSA), elliptic - curve, and integer factorization (e.g., RSA); and covers key - agreement, digital signature, and encryption. - - $ IESG - See: Internet Engineering Steering Group. - - - -Shirey Informational [Page 84] - -RFC 2828 Internet Security Glossary May 2000 - - - $ IETF - See: Internet Engineering Task Force. - - $ IKE - See: IPsec Key Exchange. - - $ IMAP4 - See: Internet Message Access Protocol, version 4. - - $ IMAP4 AUTHENTICATE - (I) A IMAP4 "command" (better described as a transaction type, or - a protocol-within-a-protocol) by which an IMAP4 client optionally - proposes a mechanism to an IMAP4 server to authenticate the client - to the server and provide other security services. (See: POP3.) - - (C) If the server accepts the proposal, the command is followed by - performing a challenge-response authentication protocol and, - optionally, negotiating a protection mechanism for subsequent POP3 - interactions. The security mechanisms that are used by IMAP4 - AUTHENTICATE--including Kerberos, GSSAPI, and S/Key--are described - in [R1731]. - - $ in the clear - (I) Not encrypted. (See: cleartext.) - - $ indirect certificate revocation list (ICRL) - (I) In X.509, a CRL that may contain certificate revocation - notifications for certificates issued by CAs other than the issuer - of the ICRL. - - $ indistinguishability - (I) An attribute of an encryption algorithm that is a - formalization of the notion that the encryption of some string is - indistinguishable from the encryption of an equal-length string of - nonsense. - - (C) Under certain conditions, this notion is equivalent to - "semantic security". - - $ information - (I) Facts and ideas, which can be represented (encoded) as various - forms of data. - - $ Information Technology Security Evaluation Criteria (ITSEC) - (N) Standard developed for use in the European Union; accommodates - a wider range of security assurance and functionality combinations - than the TCSEC. Superseded by the Common Criteria. [ITSEC] - - - - -Shirey Informational [Page 85] - -RFC 2828 Internet Security Glossary May 2000 - - - $ INFOSEC - (I) Abbreviation for "information security", referring to security - measures that implement and assure security services in computer - systems (i.e., COMPUSEC) and communication systems (i.e., COMSEC). - - $ initialization value (IV) - (I) An input parameter that sets the starting state of a - cryptographic algorithm or mode. (Sometimes called "initialization - vector" or "message indicator".) - - (C) An IV can be used to introduce cryptographic variance in - addition to that provided by a key (see: salt), and to synchronize - one cryptographic process with another. For an example of the - latter, cipher block chaining mode requires an IV. [R2405] - - $ initialization vector - (D) For consistency, ISDs SHOULD NOT use this term as a synonym - for "initialization value". - - $ insider attack - See: (secondary definition under) attack. - - $ Institute of Electrical and Electronics Engineers, Inc. (IEEE) - (N) The IEEE is a not-for-profit association of more than 330,000 - individual members in 150 countries. The IEEE produces 30 percent - of the world's published literature in electrical engineering, - computers, and control technology; holds annually more than 300 - major conferences; and has more than 800 active standards with 700 - under development. (See: Standards for Interoperable LAN/MAN - Security.) - - $ integrity - See: data integrity, correctness integrity, source integrity, - system integrity. - - $ integrity check - (D) ISDs SHOULD NOT use this term as a synonym for "cryptographic - hash" or "protected checksum", because this term unnecessarily - duplicates the meaning of other, well-established terms. - - $ intelligent threat - (I) A circumstance in which an adversary has the technical and - operational capability to detect and exploit a vulnerability and - also has the demonstrated, presumed, or inferred intent to do so. - (See: threat.) - - - - - - -Shirey Informational [Page 86] - -RFC 2828 Internet Security Glossary May 2000 - - - $ International Data Encryption Algorithm (IDEA) - (N) A patented, symmetric block cipher that uses a 128-bit key and - operates on 64-bit blocks. [Schn] (See: symmetric cryptography.) - - $ International Standard - See: (secondary definition under) ISO. - - $ International Traffic in Arms Regulations (ITAR) - (N) Rules issued by the U.S. State Department, by authority of the - Arms Export Control Act (22 U.S.C. 2778), to control export and - import of defense articles and defense services, including - information security systems, such as cryptographic systems, and - TEMPEST suppression technology. (See: Wassenaar Arrangement.) - - $ internet - $ Internet - See: internet vs. Internet. - - $ Internet Architecture Board (IAB) - (I) A technical advisory group of the ISOC, chartered by the ISOC - Trustees to provide oversight of Internet architecture and - protocols and, in the context of Internet Standards, a body to - which decisions of the IESG may be appealed. Responsible for - approving appointments to the IESG from among nominees submitted - by the IETF nominating committee. [R2026] - - $ Internet Assigned Numbers Authority (IANA) - (I) From the early days of the Internet, the IANA was chartered by - the ISOC and the U.S. Government's Federal Network Council to be - the central coordination, allocation, and registration body for - parameters for Internet protocols. Superseded by ICANN. - - $ Internet Control Message Protocol (ICMP) - (I) An Internet Standard protocol [R0792] that is used to report - error conditions during IP datagram processing and to exchange - other information concerning the state of the IP network. - - $ Internet Corporation for Assigned Names and Numbers (ICANN) - (I) The non-profit, private corporation that has assumed - responsibility for the IP address space allocation, protocol - parameter assignment, domain name system management, and root - server system management functions formerly performed under U.S. - Government contract by IANA and other entities. - - (C) The Internet Protocol Suite, as defined by the IETF and the - IESG, contains numerous parameters, such as internet addresses, - domain names, autonomous system numbers, protocol numbers, port - numbers, management information base object identifiers, including - - - -Shirey Informational [Page 87] - -RFC 2828 Internet Security Glossary May 2000 - - - private enterprise numbers, and many others. The Internet - community requires that the values used in these parameter fields - be assigned uniquely. ICANN makes those assignments as requested - and maintains a registry of the current values. - - (C) ICANN was formed in October 1998, by a coalition of the - Internet's business, technical, and academic communities. The U.S. - Government designated ICANN to serve as the global consensus - entity with responsibility for coordinating four key functions for - the Internet: the allocation of IP address space, the assignment - of protocol parameters, the management of the DNS, and the - management of the DNS root server system. - - $ Internet Draft - (I) A working document of the IETF, its areas, and its working - groups. (Other groups may also distribute working documents as - Internet Drafts.) An Internet Draft is not an archival document - like an RFC is. Instead, an Internet Draft is a preliminary or - working document that is valid for a maximum of six months and may - be updated, replaced, or made obsolete by other documents at any - time. It is inappropriate to use an Internet Draft as reference - material or to cite it other than as "work in progress." - - $ Internet Engineering Steering Group (IESG) - (I) The part of the ISOC responsible for technical management of - IETF activities and administration of the Internet Standards - Process according to procedures approved by the ISOC Trustees. - Directly responsible for actions along the "standards track", - including final approval of specifications as Internet Standards. - Composed of IETF Area Directors and the IETF chairperson, who also - chairs the IESG. [R2026] - - $ Internet Engineering Task Force (IETF) - (I) A self-organized group of people who make contributions to the - development of Internet technology. The principal body engaged in - developing Internet Standards, although not itself a part of the - ISOC. Composed of Working Groups, which are arranged into Areas - (such as the Security Area), each coordinated by one or more Area - Directors. Nominations to the IAB and the IESG are made by a - committee selected at random from regular IETF meeting attendees - who have volunteered. [R2026, R2323] - - $ Internet Message Access Protocol, version 4 (IMAP4) - (I) An Internet protocol [R2060] by which a client workstation can - dynamically access a mailbox on a server host to manipulate and - retrieve mail messages that the server has received and is holding - for the client. (See: POP3.) - - - - -Shirey Informational [Page 88] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) IMAP4 has mechanisms for optionally authenticating a client to - a server and providing other security services. (See: IMAP4 - AUTHENTICATE.) - - $ Internet Policy Registration Authority (IPRA) - (I) An X.509-compliant CA that is the top CA of the Internet - certification hierarchy operated under the auspices of the ISOC - [R1422]. (See: (PEM usage under) certification hierarchy.) - - $ Internet Protocol (IP) - (I) A Internet Standard protocol (version 4 [R0791] and version 6 - [R2460]) that moves datagrams (discrete sets of bits) from one - computer to another across an internetwork but does not provide - reliable delivery, flow control, sequencing, or other end-to-end - services that TCP provides. (See: IP address, TCP/IP.) - - (C) In the OSIRM, IP would be located at the top of layer 3. - - $ Internet Protocol security (IPsec) - (I) (1.) The name of the IETF working group that is specifying a - security architecture [R2401] and protocols to provide security - services for Internet Protocol traffic. (2.) A collective name for - that architecture and set of protocols. (Implementation of IPsec - protocols is optional for IP version 4, but mandatory for IP - version 6.) (See: Internet Protocol Security Option.) - - (C) Note that the letters "sec" are lower-case. - - (C) The IPsec architecture specifies (a) security protocols (AH - and ESP), (b) security associations (what they are, how they work, - how they are managed, and associated processing), (c) key - management (IKE), and (d) algorithms for authentication and - encryption. The set of security services include access control - service, connectionless data integrity service, data origin - authentication service, protection against replays (detection of - the arrival of duplicate datagrams, within a constrained window), - data confidentiality service, and limited traffic flow - confidentiality. - - $ Internet Protocol Security Option (IPSO) - (I) Refers to one of three types of IP security options, which are - fields that may be added to an IP datagram for the purpose of - carrying security information about the datagram. (See: IPsec.) - - (D) ISDs SHOULD NOT use this term without a modifier to indicate - which of the three types is meant. - - - - - -Shirey Informational [Page 89] - -RFC 2828 Internet Security Glossary May 2000 - - - 1. "DoD Basic Security Option" (IP option type 130): Defined for - use on U.S. Department of Defense common user data networks. - Identifies the Defense classification level at which the - datagram is to be protected and the protection authorities - whose rules apply to the datagram. [R1108] - - A "protection authority" is a National Access Program (e.g., - GENSER, SIOP-ESI, SCI, NSA, Department of Energy) or Special - Access Program that specifies protection rules for transmission - and processing of the information contained in the datagram. - [R1108] - - 2. "DoD Extended Security Option" (IP option type 133): Permits - additional security labeling information, beyond that present - in the Basic Security Option, to be supplied in the datagram to - meet the needs of registered authorities. [R1108] - - 3. "Common IP Security Option" (CIPSO) (IP option type 134): - Designed by TSIG to carry hierarchic and non-hierarchic - security labels. (Formerly called "Commercial IP Security - Option".) Was published as Internet-Draft [CIPSO]; not advanced - to RFC. - - $ Internet Protocol Suite - See: (secondary definition under) Internet. - - $ Internet Security Association and Key Management Protocol (ISAKMP) - (I) An Internet IPsec protocol [R2408] to negotiate, establish, - modify, and delete security associations, and to exchange key - generation and authentication data, independent of the details of - any specific key generation technique, key establishment protocol, - encryption algorithm, or authentication mechanism. - - (C) ISAKMP supports negotiation of security associations for - protocols at all TCP/IP layers. By centralizing management of - security associations, ISAKMP reduces duplicated functionality - within each protocol. ISAKMP can also reduce connection setup - time, by negotiating a whole stack of services at once. Strong - authentication is required on ISAKMP exchanges, and a digital - signature algorithm based on asymmetric cryptography is used - within ISAKMP's authentication component. - - $ Internet Society (ISOC) - (I) A professional society concerned with Internet development - (including technical Internet Standards); with how the Internet is - and can be used; and with social, political, and technical issues - - - - - -Shirey Informational [Page 90] - -RFC 2828 Internet Security Glossary May 2000 - - - that result. The ISOC Board of Trustees approves appointments to - the IAB from among nominees submitted by the IETF nominating - committee. [R2026] - - $ Internet Standard - (I) A specification, approved by the IESG and published as an RFC, - that is stable and well-understood, is technically competent, has - multiple, independent, and interoperable implementations with - substantial operational experience, enjoys significant public - support, and is recognizably useful in some or all parts of the - Internet. [R2026] (See: RFC.) - - (C) The Internet Standards Process is an activity of the ISOC and - is organized and managed by the IAB and the IESG. The process is - concerned with all protocols, procedures, and conventions used in - or by the Internet, whether or not they are part of the Internet - Protocol Suite. The "Internet Standards Track" has three levels of - increasing maturity: Proposed Standard, Draft Standard, and - Standard. (See: (standards levels under) ISO.) - - $ Internet Standards document (ISD) - (C) In this Glossary, this term refers to an RFC, Internet-Draft, - or other item that is produced as part of the Internet Standards - Process [R2026]. However, neither the term nor the abbreviation is - widely accepted and, therefore, SHOULD NOT be used in an ISD - unless it is accompanied by an explanation like this. (See: - Internet Standard.) - - $ internet vs. Internet - 1. (I) Not capitalized: A popular abbreviation for "internetwork". - - 2. (I) Capitalized: "The Internet" is the single, interconnected, - worldwide system of commercial, government, educational, and other - computer networks that share the set of protocols specified by the - IAB [R2026] and the name and address spaces managed by the ICANN. - - (C) The protocol set is named the "Internet Protocol Suite". It - also is popularly known as "TCP/IP", because TCP and IP are two of - its fundamental components. These protocols enable a user of any - one of the networks in the Internet to communicate with, or use - services located on, any of the other networks. - - (C) Although the Internet does have architectural principles - [R1958], no Internet Standard formally defines a layered reference - model for the IPS that is similar to the OSIRM. However, Internet - community documents do refer (inconsistently) to layers: - application, socket, transport, internetwork, network, data link, - - - - -Shirey Informational [Page 91] - -RFC 2828 Internet Security Glossary May 2000 - - - and physical. In this Glossary, Internet layers are referred to by - name to avoid confusing them with OSIRM layers, which are referred - to by number. - - $ internetwork - (I) A system of interconnected networks; a network of networks. - Usually shortened to "internet". (See: internet vs. Internet.) - - (C) An internet is usually built using OSI layer 3 gateways to - connect a set of subnetworks. When the subnetworks differ in the - OSI layer 3 protocol service they provide, the gateways sometimes - implement a uniform internetwork protocol (e.g., IP) that operates - at the top of layer 3 and hides the underlying heterogeneity from - hosts that use communication services provided by the internet. - (See: router.) - - $ intranet - (I) A computer network, especially one based on Internet - technology, that an organization uses for its own internal, and - usually private, purposes and that is closed to outsiders. (See: - extranet, virtual private network.) - - $ intruder - (I) An entity that gains or attempts to gain access to a system or - system resource without having authorization to do so. (See: - cracker.) - - $ intrusion - See: security intrusion. - - $ intrusion detection - (I) A security service that monitors and analyzes system events - for the purpose of finding, and providing real-time or near real- - time warning of, attempts to access system resources in an - unauthorized manner. - - $ invalidity date - (N) An X.509 CRL entry extension that "indicates the date at which - it is known or suspected that the [revoked certificate's private - key] was compromised or that the certificate should otherwise be - considered invalid" [X509]. - - (C) This date may be earlier than the revocation date in the CRL - entry, and may even be earlier than the date of issue of earlier - CRLs. However, the invalidity date is not, by itself, sufficient - for purposes of non-repudiation service. For example, to - - - - - -Shirey Informational [Page 92] - -RFC 2828 Internet Security Glossary May 2000 - - - fraudulently repudiate a validly-generated signature, a private - key holder may falsely claim that the key was compromised at some - time in the past. - - $ IP - See: Internet Protocol. - - $ IP address - (I) A computer's internetwork address that is assigned for use by - the Internet Protocol and other protocols. - - (C) An IP version 4 [R0791] address is written as a series of four - 8-bit numbers separated by periods. For example, the address of - the host named "rosslyn.bbn.com" is 192.1.7.10. - - (C) An IP version 6 [R2373] address is written as x:x:x:x:x:x:x:x, - where each "x" is the hexadecimal value of one of the eight 16-bit - parts of the address. For example, 1080:0:0:0:8:800:200C:417A and - FEDC:BA98:7654:3210:FEDC:BA98:7654:3210. - - $ IP Security Option - See: Internet Protocol Security Option. - - $ IPRA - See: Internet Policy Registration Authority. - - $ IPsec - See: Internet Protocol security. - - $ IPsec Key Exchange (IKE) - (I) An Internet, IPsec, key-establishment protocol [R2409] (partly - based on OAKLEY) that is intended for putting in place - authenticated keying material for use with ISAKMP and for other - security associations, such as in AH and ESP. - - $ IPSO - See: Internet Protocol Security Option. - - $ ISAKMP - See: Internet Security Association and Key Management Protocol. - - $ ISD - See: Internet Standards document. - - $ ISO - (I) International Organization for Standardization, a voluntary, - non-treaty, non-government organization, established in 1947, with - voting members that are designated standards bodies of - - - -Shirey Informational [Page 93] - -RFC 2828 Internet Security Glossary May 2000 - - - participating nations and non-voting observer organizations. (See: - ANSI, ITU-T.) - - (C) Legally, ISO is a Swiss, non-profit, private organization. ISO - and the IEC (the International Electrotechnical Commission) form - the specialized system for worldwide standardization. National - bodies that are members of ISO or IEC participate in developing - international standards through ISO and IEC technical committees - that deal with particular fields of activity. Other international - governmental and non-governmental organizations, in liaison with - ISO and IEC, also take part. (ANSI is the U.S. voting member of - ISO. ISO is a class D member of ITU-T.) - - (C) The ISO standards development process has four levels of - increasing maturity: Working Draft (WD), Committee Draft (CD), - Draft International Standard (DIS), and International Standard - (IS). (See: (standards track levels under) Internet Standard.) In - information technology, ISO and IEC have a joint technical - committee, ISO/IEC JTC 1. DISs adopted by JTC 1 are circulated to - national bodies for voting, and publication as an IS requires - approval by at least 75% of the national bodies casting a vote. - - $ ISOC - See: Internet Society. - - $ issue (a digital certificate or CRL) - (I) Generate and sign a digital certificate (or CRL) and, usually, - distribute it and make it available to potential certificate users - (or CRL users). (See: certificate creation.) - - (C) The ABA Guidelines [ABA] explicitly limit this term to - certificate creation, and exclude the act of publishing. In - general usage, however, "issuing" a digital certificate (or CRL) - includes not only certificate creation but also making it - available to potential users, such as by storing it in a - repository or other directory or otherwise publishing it. - - $ issuer - 1. (I) "Issuer" of a certificate or CRL: The CA that signs the - digital certificate or CRL. - - (C) An X.509 certificate always includes the issuer's name. The - name may include a common name value. - - 2. (N) "Issuer" of a payment card: SET usage: "The financial - institution or its agent that issues the unique primary account - number to the cardholder for the payment card brand." [SET2] - - - - -Shirey Informational [Page 94] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) The institution that establishes the account for a cardholder - and issues the payment card also guarantees payment for authorized - transactions that use the card in accordance with card brand - regulations and local legislation. [SET1] - - $ ITAR - See: International Traffic in Arms Regulations. - - $ ITSEC - See: Information Technology System Evaluation Criteria. - - $ ITU-T - (N) International Telecommunications Union, Telecommunication - Standardization Sector (formerly "CCITT"), a United Nations treaty - organization that is composed mainly of postal, telephone, and - telegraph authorities of the member countries and that publishes - standards called "Recommendations". (See: X.400, X.500.) - - (C) The Department of State represents the United States. ITU-T - works on many kinds of communication systems. ITU-T cooperates - with ISO on communication protocol standards, and many - Recommendations in that area are also published as an ISO standard - with an ISO name and number. - - $ IV - See: initialization value. - - $ KDC - See: Key Distribution Center. - - $ KEA - See: Key Exchange Algorithm. - - $ KEK - See: key-encrypting key. - - $ Kerberos - (N) A system developed at the Massachusetts Institute of - Technology that depends on passwords and symmetric cryptography - (DES) to implement ticket-based, peer entity authentication - service and access control service distributed in a client-server - network environment. [R1510, Stei] - - (C) Kerberos was developed by Project Athena and is named for the - three-headed dog guarding Hades. - - $ key - See: cryptographic key. - - - -Shirey Informational [Page 95] - -RFC 2828 Internet Security Glossary May 2000 - - - $ key agreement (algorithm or protocol) - (I) A key establishment method (especially one involving - asymmetric cryptography) by which two or more entities, without - prior arrangement except a public exchange of data (such as public - keys), each computes the same key value. I.e., each can - independently generate the same key value, but that key cannot be - computed by other entities. (See: Diffie-Hellman, key - establishment, Key Exchange Algorithm, key transport.) - - (O) "A method for negotiating a key value on line without - transferring the key, even in an encrypted form, e.g., the Diffie- - Hellman technique." [X509] - - (O) "The procedure whereby two different parties generate shared - symmetric keys such that any of the shared symmetric keys is a - function of the information contributed by all legitimate - participants, so that no party [alone] can predetermine the value - of the key." [A9042] - - (C) For example, a message originator and the intended recipient - can each use their own private key and the other's public key with - the Diffie-Hellman algorithm to first compute a shared secret - value and, from that value, derive a session key to encrypt the - message. - - $ key authentication - (N) "The assurance of the legitimate participants in a key - agreement that no non-legitimate party possesses the shared - symmetric key." [A9042] - - $ key center - (I) A centralized key distribution process (used in symmetric - cryptography), usually a separate computer system, that uses key- - encrypting keys (master keys) to encrypt and distribute session - keys needed in a community of users. - - (C) An ANSI standard [A9017] defines two types of key center: key - distribution center and key translation center. - - $ key confirmation - (N) "The assurance of the legitimate participants in a key - establishment protocol that the intended parties sharing the - symmetric key actually possess the shared symmetric key." [A9042] - - $ key distribution - (I) A process that delivers a cryptographic key from the location - where it is generated to the locations where it is used in a - cryptographic algorithm. (See: key management.) - - - -Shirey Informational [Page 96] - -RFC 2828 Internet Security Glossary May 2000 - - - $ key distribution center (KDC) - (I) A type of key center (used in symmetric cryptography) that - implements a key distribution protocol to provide keys (usually, - session keys) to two (or more) entities that wish to communicate - securely. (See: key translation center.) - - (C) A KDC distributes keys to Alice and Bob, who (a) wish to - communicate with each other but do not currently share keys, (b) - each share a KEK with the KDC, and (c) may not be able to generate - or acquire keys by themselves. Alice requests the keys from the - KDC. The KDC generates or acquires the keys and makes two - identical sets. The KDC encrypts one set in the KEK it shares with - Alice, and sends that encrypted set to Alice. The KDC encrypts the - second set in the KEK it shares with Bob, and either sends that - encrypted set to Alice for her to forward to Bob, or sends it - directly to Bob (although the latter option is not supported in - the ANSI standard [A9017]). - - $ key encapsulation - See: (secondary definition under) key recovery. - - $ key-encrypting key (KEK) - (I) A cryptographic key that is used to encrypt other keys, either - DEKs or other KEKs, but usually is not used to encrypt application - data. - - $ key escrow - See: (secondary definition under) key recovery. - - $ key establishment (algorithm or protocol) - (I) A process that combines the key generation and key - distribution steps needed to set up or install a secure - communication association. (See: key agreement, key transport.) - - (O) "The procedure to share a symmetric key among different - parties by either key agreement or key transport." [A9042] - - (C) Key establishment involves either key agreement or key - transport: - - - Key transport: One entity generates a secret key and securely - sends it to the other entity. (Or each entity generates a - secret value and securely sends it to the other entity, where - the two values are combined to form a secret key.) - - - Key agreement: No secret is sent from one entity to another. - Instead, both entities, without prior arrangement except a - public exchange of data, compute the same secret value. I.e., - - - -Shirey Informational [Page 97] - -RFC 2828 Internet Security Glossary May 2000 - - - each can independently generate the same value, but that value - cannot be computed by other entities. - - $ Key Exchange Algorithm (KEA) - (N) A key agreement algorithm [NIST] that is similar to the - Diffie-Hellman algorithm, uses 1024-bit asymmetric keys, and was - developed and formerly classified at the "Secret" level by NSA. - (See: CAPSTONE, CLIPPER, FORTEZZA, SKIPJACK.) - - (C) On 23 June 1998, the NSA announced that KEA had been - declassified. - - $ key generation - (I) A process that creates the sequence of symbols that comprise a - cryptographic key. (See: key management.) - - $ key generator - 1. (I) An algorithm that uses mathematical rules to - deterministically produce a pseudo-random sequence of - cryptographic key values. - - 2. (I) An encryption device that incorporates a key generation - mechanism and applies the key to plaintext (e.g., by exclusive OR- - ing the key bit string with the plaintext bit string) to produce - ciphertext. - - $ key length - (I) The number of symbols (usually bits) needed to be able to - represent any of the possible values of a cryptographic key. (See: - key space.) - - $ key lifetime - (N) MISSI usage: An attribute of a MISSI key pair that specifies a - time span that bounds the validity period of any MISSI X.509 - public-key certificate that contains the public component of the - pair. (See: cryptoperiod.) - - $ key management - (I) The process of handling and controlling cryptographic keys and - related material (such as initialization values) during their life - cycle in a cryptographic system, including ordering, generating, - distributing, storing, loading, escrowing, archiving, auditing, - and destroying the material. (See: key distribution, key escrow, - keying material, public-key infrastructure.) - - (O) "The generation, storage, distribution, deletion, archiving - and application of keys in accordance with a security policy." - [I7498 Part 2] - - - -Shirey Informational [Page 98] - -RFC 2828 Internet Security Glossary May 2000 - - - (O) "The activities involving the handling of cryptographic keys - and other related security parameters (e.g., IVs, counters) during - the entire life cycle of the keys, including their generation, - storage, distribution, entry and use, deletion or destruction, and - archiving." [FP140] - - $ Key Management Protocol (KMP) - (N) A protocol to establish a shared symmetric key between a pair - (or a group) of users. (One version of KMP was developed by SDNS, - and another by SILS.) - - $ key material identifier (KMID) - (N) MISSI usage: A 64-bit identifier that is assigned to a key - pair when the public key is bound in a MISSI X.509 public-key - certificate. - - $ key pair - (I) A set of mathematically related keys--a public key and a - private key--that are used for asymmetric cryptography and are - generated in a way that makes it computationally infeasible to - derive the private key from knowledge of the public key (e.g., - see: Diffie-Hellman, Rivest-Shamir-Adleman). - - (C) A key pair's owner discloses the public key to other system - entities so they can use the key to encrypt data, verify a digital - signature, compute a protected checksum, or generate a key in a - key agreement algorithm. The matching private key is kept secret - by the owner, who uses it to decrypt data, generate a digital - signature, verify a protected checksum, or generate a key in a key - agreement algorithm. - - $ key recovery - 1. (I) A process for learning the value of a cryptographic key - that was previously used to perform some cryptographic operation. - (See: cryptanalysis.) - - 2. (I) Techniques that provide an intentional, alternate (i.e., - secondary) means to access the key used for data confidentiality - service in an encrypted association. [DOD4] - - (C) We assume that the encryption mechanism has a primary means of - obtaining the key through a key establishment algorithm or - protocol. For the secondary means, there are two classes of key - recovery techniques--key escrow and key encapsulation: - - - - - - - -Shirey Informational [Page 99] - -RFC 2828 Internet Security Glossary May 2000 - - - - "Key escrow": A key recovery technique for storing knowledge of - a cryptographic key or parts thereof in the custody of one or - more third parties called "escrow agents", so that the key can - be recovered and used in specified circumstances. - - Key escrow is typically implemented with split knowledge - techniques. For example, the Escrowed Encryption Standard - [FP185] entrusts two components of a device-unique split key to - separate escrow agents. The agents provide the components only - to someone legally authorized to conduct electronic - surveillance of telecommunications encrypted by that specific - device. The components are used to reconstruct the device- - unique key, and it is used to obtain the session key needed to - decrypt communications. - - - "Key encapsulation": A key recovery technique for storing - knowledge of a cryptographic key by encrypting it with another - key and ensuring that that only certain third parties called - "recovery agents" can perform the decryption operation to - retrieve the stored key. - - Key encapsulation typically allows direct retrieval of the - secret key used to provide data confidentiality. - - $ key space - (I) The range of possible values of a cryptographic key; or the - number of distinct transformations supported by a particular - cryptographic algorithm. (See: key length.) - - $ key translation center - (I) A type of key center (used in a symmetric cryptography) that - implements a key distribution protocol to convey keys between two - (or more) parties who wish to communicate securely. (See: key - distribution center.) - - (C) A key translation center translates keys for future - communication between Bob and Alice, who (a) wish to communicate - with each other but do not currently share keys, (b) each share a - KEK with the center, and (c) have the ability to generate or - acquire keys by themselves. Alice generates or acquires a set of - keys for communication with Bob. Alice encrypts the set in the KEK - she shares with the center and sends the encrypted set to the - center. The center decrypts the set, reencrypts the set in the KEK - it shares with Bob, and either sends that encrypted set to Alice - for her to forward to Bob, or sends it directly to Bob (although - direct distribution is not supported in the ANSI standard - [A9017]). - - - - -Shirey Informational [Page 100] - -RFC 2828 Internet Security Glossary May 2000 - - - $ key transport (algorithm or protocol) - (I) A key establishment method by which a secret key is generated - by one entity in a communication association and securely sent to - another entity in the association. (See: key agreement.) - - (O) "The procedure to send a symmetric key from one party to other - parties. As a result, all legitimate participants share a common - symmetric key in such a way that the symmetric key is determined - entirely by one party." [A9042] - - (C) For example, a message originator can generate a random - session key and then use the Rivest-Shamir-Adleman algorithm to - encrypt that key with the public key of the intended recipient. - - $ key update - (I) Derive a new key from an existing key. (See: certificate - rekey.) - - $ key validation - (N) "The procedure for the receiver of a public key to check that - the key conforms to the arithmetic requirements for such a key in - order to thwart certain types of attacks." [A9042] - - $ keyed hash - (I) A cryptographic hash (e.g., [R1828]) in which the mapping to a - hash result is varied by a second input parameter that is a - cryptographic key. (See: checksum.) - - (C) If the input data object is changed, a new hash result cannot - be correctly computed without knowledge of the secret key. Thus, - the secret key protects the hash result so it can be used as a - checksum even when there is a threat of an active attack on the - data. There are least two forms of keyed hash: - - - A function based on a keyed encryption algorithm. (E.g., see: - Data Authentication Code.) - - - A function based on a keyless hash that is enhanced by - combining (e.g., by concatenating) the input data object - parameter with a key parameter before mapping to the hash - result. (E.g., see: HMAC.) - - $ keying material - (I) Data (such as keys, key pairs, and initialization values) - needed to establish and maintain a cryptographic security - association. - - - - - -Shirey Informational [Page 101] - -RFC 2828 Internet Security Glossary May 2000 - - - $ KMID - See: key material identifier. - - $ known-plaintext attack - (I) A cryptanalysis technique in which the analyst tries to - determine the key from knowledge of some plaintext-ciphertext - pairs (although the analyst may also have other clues, such as the - knowing the cryptographic algorithm). - - $ L2F - See: Layer 2 Forwarding Protocol. - - $ L2TP - See: Layer 2 Tunneling Protocol. - - $ label - See: security label. - - $ Language of Temporal Ordering Specification (LOTOS) - (N) A language (ISO 8807-1990) for formal specification of - computer network protocols; describes the order in which events - occur. - - $ lattice model - (I) A security model for flow control in a system, based on the - lattice that is formed by the finite security levels in a system - and their partial ordering. [Denn] (See: flow control, security - level, security model.) - - (C) The model describes the semantic structure formed by a finite - set of security levels, such as those used in military - organizations. - - (C) A lattice is a finite set together with a partial ordering on - its elements such that for every pair of elements there is a least - upper bound and a greatest lower bound. For example, a lattice is - formed by a finite set S of security levels -- i.e., a set S of all - ordered pairs (x, c), where x is one of a finite set X of - hierarchically ordered classification levels (X1, ..., Xm), and c - is a (possibly empty) subset of a finite set C of non-hierarchical - categories (C1, ..., Cn) -- together with the "dominate" relation. - (See: dominate.) - - $ Law Enforcement Access Field (LEAF) - (N) A data item that is automatically embedded in data encrypted - by devices (e.g., see: CLIPPER chip) that implement the Escrowed - Encryption Standard. - - - - -Shirey Informational [Page 102] - -RFC 2828 Internet Security Glossary May 2000 - - - $ Layer 2 Forwarding Protocol (L2F) - (N) An Internet protocol (originally developed by Cisco - Corporation) that uses tunneling of PPP over IP to create a - virtual extension of a dial-up link across a network, initiated by - the dial-up server and transparent to the dial-up user. (See: - L2TP.) - - $ Layer 2 Tunneling Protocol (L2TP) - (N) An Internet client-server protocol that combines aspects of - PPTP and L2F and supports tunneling of PPP over an IP network or - over frame relay or other switched network. (See: virtual private - network.) - - (C) PPP can in turn encapsulate any OSI layer 3 protocol. Thus, - L2TP does not specify security services; it depends on protocols - layered above and below it to provide any needed security. - - $ LDAP - See: Lightweight Directory Access Protocol. - - $ least privilege - (I) The principle that a security architecture should be designed - so that each system entity is granted the minimum system resources - and authorizations that the entity needs to do its work. (See: - economy of mechanism.) - - (C) This principle tends to limit damage that can be caused by an - accident, error, or unauthorized act. - - $ Lightweight Directory Access Protocol (LDAP) - (N) A client-server protocol that supports basic use of the X.500 - Directory (or other directory servers) without incurring the - resource requirements of the full Directory Access Protocol (DAP). - [R1777] - - (C) Designed for simple management and browser applications that - provide simple read/write interactive directory service. Supports - both simple authentication and strong authentication of the client - to the directory server. - - $ link - (I) World Wide Web usage: See: hyperlink. - - (I) Subnetwork usage: A point-to-point communication channel - connecting two subnetwork relays (especially one between two - packet switches) that is implemented at OSI layer 2. (See: link - encryption.) - - - - -Shirey Informational [Page 103] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) The relay computers assume that links are logically passive. - If a computer at one end of a link sends a sequence of bits, the - sequence simply arrives at the other end after a finite time, - although some bits may have been changed either accidentally - (errors) or by active wiretapping. - - $ link-by-link encryption - $ link encryption - (I) Stepwise protection of data that flows between two points in a - network, provided by encrypting data separately on each network - link, i.e., by encrypting data when it leaves a host or subnetwork - relay and decrypting when it arrives at the next host or relay. - Each link may use a different key or even a different algorithm. - [R1455] (See: end-to-end encryption.) - - $ logic bomb - (I) Malicious logic that activates when specified conditions are - met. Usually intended to cause denial of service or otherwise - damage system resources. (See: Trojan horse, virus, worm.) - - $ login - (I) The act of a system entity gaining access to a session in - which the entity can use system resources; usually accomplished by - providing a user name and password to an access control system - that authenticates the user. - - (C) Derives from "log" file", a security audit trail that records - security events, such as the beginning of sessions, and who - initiates them. - - $ LOTOS - See: Language of Temporal Ordering Specification. - - $ MAC - See: mandatory access control, Message Authentication Code. - - $ malicious logic - (I) Hardware, software, or firmware that is intentionally included - or inserted in a system for a harmful purpose. (See: logic bomb, - Trojan horse, virus, worm.) - - $ malware - (I) A contraction of "malicious software". (See: malicious logic.) - - (D) ISDs SHOULD NOT use this term because it is not listed in most - dictionaries and could confuse international readers. - - - - - -Shirey Informational [Page 104] - -RFC 2828 Internet Security Glossary May 2000 - - - $ man-in-the-middle - (I) A form of active wiretapping attack in which the attacker - intercepts and selectively modifies communicated data in order to - masquerade as one or more of the entities involved in a - communication association. (See: hijack attack, piggyback attack.) - - (C) For example, suppose Alice and Bob try to establish a session - key by using the Diffie-Hellman algorithm without data origin - authentication service. A "man in the middle" could (a) block - direct communication between Alice and Bob and then (b) masquerade - as Alice sending data to Bob, (c) masquerade as Bob sending data - to Alice, (d) establish separate session keys with each of them, - and (e) function as a clandestine proxy server between them in - order to capture or modify sensitive information that Alice and - Bob think they are sending only to each other. - - $ mandatory access control (MAC) - (I) An access control service that enforces a security policy - based on comparing (a) security labels (which indicate how - sensitive or critical system resources are) with (b) security - clearances (which indicate system entities are eligible to access - certain resources). (See: discretionary access control, rule-based - security policy.) - - (C) This kind of access control is called "mandatory" because an - entity that has clearance to access a resource may not, just by - its own volition, enable another entity to access that resource. - - (O) "A means of restricting access to objects based on the - sensitivity (as represented by a label) of the information - contained in the objects and the formal authorization (i.e., - clearance) of subjects to access information of such sensitivity." - [DOD1] - - $ manipulation detection code - (D) ISDs SHOULD NOT use this term as a synonym for "checksum" - because the word "manipulation" implies protection against active - attacks, which an ordinary checksum might not provide. Instead, if - such protection is intended, use "protected checksum" or some - particular type thereof, depending on which is meant. If such - protection is not intended, use "error detection code" or some - specific type of checksum that is not protected. - - $ masquerade attack - (I) A type of attack in which one system entity illegitimately - poses as (assumes the identity of) another entity. (See: spoofing - attack.) - - - - -Shirey Informational [Page 105] - -RFC 2828 Internet Security Glossary May 2000 - - - $ MCA - See: merchant certificate authority. - - $ MD2 - (N) A cryptographic hash [R1319] that produces a 128-bit hash - result, was designed by Ron Rivest, and is similar to MD4 and MD5 - but slower. (See: message digest.) - - $ MD4 - (N) A cryptographic hash [R1320] that produces a 128-bit hash - result and was designed by Ron Rivest. (See: message digest and - SHA-1.) - - $ MD5 - (N) A cryptographic hash [R1321] that produces a 128-bit hash - result and was designed by Ron Rivest to be an improved version of - MD4. - - $ merchant - (O) SET usage: "A seller of goods, services, and/or other - information who accepts payment for these items electronically." - [SET2] A merchant may also provide electronic selling services - and/or electronic delivery of items for sale. With SET, the - merchant can offer its cardholders secure electronic interactions, - but a merchant that accepts payment cards is required to have a - relationship with an acquirer. [SET1, SET2] - - $ merchant certificate - (O) SET usage: A public-key certificate issued to a merchant. - Sometimes used to refer to a pair of such certificates where one - is for digital signature use and the other is for encryption. - - $ merchant certification authority (MCA) - (O) SET usage: A CA that issues digital certificates to merchants - and is operated on behalf of a payment card brand, an acquirer, or - another party according to brand rules. Acquirers verify and - approve requests for merchant certificates prior to issuance by - the MCA. An MCA does not issue a CRL, but does distribute CRLs - issued by root CAs, brand CAs, geopolitical CAs, and payment - gateway CAs. [SET2] - - $ mesh PKI - (I) A non-hierarchical PKI architecture in which there are several - trusted CAs rather than a single root. Each certificate user bases - path validations on the public key of one of the trusted CAs, - usually the one that issued that user's own public-key - certificate. Rather than having superior-to-subordinate - - - - -Shirey Informational [Page 106] - -RFC 2828 Internet Security Glossary May 2000 - - - relationships between CAs, the relationships are peer-to-peer, and - CAs issue cross-certificates to each other. (See: hierarchical - PKI, trust-file PKI.) - - $ message authentication code vs. Message Authentication Code (MAC) - 1. (N) Capitalized: "(The) Message Authentication Code" refers to - an ANSI standard for a checksum that is computed with a keyed hash - that is based on DES. [A9009] (Also known as the U.S. Government - standard Data Authentication Code. [FP113]) - - (C) The ANSI standard MAC algorithm is equivalent to cipher block - chaining with IV = 0. - - 2. (D) Not capitalized: ISDs SHOULD NOT use the uncapitalized form - "message authentication code", because this term mixes concepts in - a potentially misleading way. Instead, use "checksum", "error - detection code", "hash", "keyed hash", "Message Authentication - Code", or "protected checksum", depending on what is meant. (See: - authentication code.) - - (C) In the uncapitalized form, the word "message" is misleading - because it implies that the mechanism is particularly suitable for - or limited to electronic mail (see: Message Handling Systems), the - word "authentication" is misleading because the mechanism - primarily serves a data integrity function rather than an - authentication function, and the word "code" is misleading because - it implies that either encoding or encryption is involved or that - the term refers to computer software. - - $ message digest - (D) ISDs SHOULD NOT use this term as a synonym for "hash result" - because it unnecessarily duplicates the meaning of the other, more - general term and mixes concepts in a potentially misleading way. - (See: cryptographic hash, Message Handling System.) - - $ Message Handling Systems - (I) A ITU-T/ISO system concept, which encompasses the notion of - electronic mail but defines more comprehensive OSI systems and - services that enable users to exchange messages on a store-and- - forward basis. (The ISO equivalent is "Message Oriented Text - Interchange System".) (See: X.400.) - - $ message indicator - (D) ISDs SHOULD NOT use this term as a synonym for "initialization - value" because it mixes concepts in a potentially misleading way. - - - - - - -Shirey Informational [Page 107] - -RFC 2828 Internet Security Glossary May 2000 - - - $ message integrity check - $ message integrity code - (D) ISDs SHOULD NOT use these terms because they mix concepts in a - potentially misleading way. (The word "message" is misleading - because it suggests that the mechanism is particularly suitable - for or limited to electronic mail. The word "code" is misleading - because it suggests that either encoding or encryption is - involved, or that the term refers to computer software.) Instead, - use "checksum", "error detection code", "hash", "keyed hash", - "Message Authentication Code", or "protected checksum", depending - on what is meant. - - $ Message Security Protocol (MSP) - (N) A secure message handling protocol [SDNS7] for use with X.400 - and Internet mail protocols. Developed by NSA's SDNS program and - used in the U.S. Defense Message System. - - $ MHS - See: message handling system. - - $ MIME - See: Multipurpose Internet Mail Extensions. - - $ MIME Object Security Services (MOSS) - (I) An Internet protocol [R1848] that applies end-to-end - encryption and digital signature to MIME message content, using - symmetric cryptography for encryption and asymmetric cryptography - for key distribution and signature. MOSS is based on features and - specifications of PEM. (See: S/MIME.) - - $ Minimum Interoperability Specification for PKI Components (MISPC) - (N) A technical description to provide a basis for interoperation - between PKI components from different vendors; consists primarily - of a profile of certificate and CRL extensions and a set of - transactions for PKI operation. [MISPC] - - $ MISPC - See: Minimum Interoperability Specification for PKI Components. - - $ MISSI - (N) Multilevel Information System Security Initiative, an NSA - program to encourage development of interoperable, modular - products for constructing secure network information systems in - support of a wide variety of Government missions. (See: MSP.) - - - - - - - -Shirey Informational [Page 108] - -RFC 2828 Internet Security Glossary May 2000 - - - $ MISSI user - (O) MISSI usage: A system entity that is the subject of one or - more MISSI X.509 public-key certificates issued under a MISSI - certification hierarchy. (See: personality.) - - (C) MISSI users include both end users and the authorities that - issue certificates. A MISSI user is usually a person but may be a - machine or other automated process. Some machines are required to - operate non-stop. To avoid downtime needed to exchange the - FORTEZZA cards of machine operators at shift changes, the machines - may be issued their own cards, as if they were persons. - - $ mode - $ mode of operation - (I) Encryption usage: A technique for enhancing the effect of a - cryptographic algorithm or adapting the algorithm for an - application, such as applying a block cipher to a sequence of data - blocks or a data stream. (See: electronic codebook, cipher block - chaining, cipher feedback, output feedback.) - - (I) System operation usage: A type of security policy that states - the range of classification levels of information that a system is - permitted to handle and the range of clearances and authorizations - of users who are permitted to access the system. (See: dedicated - security mode, multilevel security mode, partitioned security - mode, system high security mode.) - - $ modulus - (I) The defining constant in modular arithmetic, and usually a - part of the public key in asymmetric cryptography that is based on - modular arithmetic. (See: Diffie-Hellman, Rivest-Shamir-Adleman.) - - $ Morris Worm - (I) A worm program written by Robert T. Morris, Jr. that flooded - the ARPANET in November, 1988, causing problems for thousands of - hosts. (See: worm.) - - $ MOSS - See: MIME Object Security Services. - - $ MSP - See: Message Security Protocol. - - $ multilevel secure (MLS) - (I) A class of system that has system resources (particularly - stored information) at more than one security level (i.e., has - different types of sensitive resources) and that permits - - - - -Shirey Informational [Page 109] - -RFC 2828 Internet Security Glossary May 2000 - - - concurrent access by users who differ in security clearance and - need-to-know, but is able to prevent each user from accessing - resources for which the user lacks authorization. - - $ multilevel security mode - (I) A mode of operation of an information system, that allows two - or more classification levels of information to be processed - concurrently within the same system when not all users have a - clearance or formal access authorization for all data handled by - the system. - - (C) This mode is defined formally in U.S. Department of Defense - policy regarding system accreditation [DOD2], but the term is also - used outside the Defense Department and outside the Government. - - $ Multipurpose Internet Mail Extensions (MIME) - (I) An Internet protocol [R2045] that enhances the basic format of - Internet electronic mail messages [R0822] to be able to use - character sets other than US-ASCII for textual headers and text - content, and to carry non-textual and multi-part content. (See: - S/MIME.) - - $ mutual suspicion - (I) The state that exists between two interacting system entities - in which neither entity can trust the other to function correctly - with regard to some security requirement. - - $ National Computer Security Center (NCSC) - (N) A U.S. Department of Defense organization, housed in NSA, that - has responsibility for encouraging widespread availability of - trusted computer systems throughout the Federal Government. It has - established criteria for, and performs evaluations of, computer - and network systems that have a trusted computing base. (See: - Evaluated Products List, Rainbow Series, TCSEC.) - - $ National Information Assurance Partnership (NIAP) - (N) An organization created by NIST and NSA to enhance the quality - of commercial products for information security and increase - consumer confidence in those products through objective evaluation - and testing methods. - - (C) NIAP is registered, through the U.S. Department of Defense, as - a National Performance Review Reinvention Laboratory. NIAP - functions include the following: - - - Developing tests, test methods, and other tools that developers - and testing laboratories may use to improve and evaluate - security products. - - - -Shirey Informational [Page 110] - -RFC 2828 Internet Security Glossary May 2000 - - - - Collaborating with industry and others on research and testing - programs. - - Using the Common Criteria to develop protection profiles and - associated test sets for security products and systems. - - Cooperating with the NIST National Voluntary Laboratory - Accreditation Program to develop a program to accredit private- - sector laboratories for the testing of information security - products using the Common Criteria. - - Working to establish a formal, international mutual recognition - scheme for a Common Criteria-based evaluation. - - $ National Institute of Standards and Technology (NIST) - (N) A U.S. Department of Commerce agency that promotes U.S. - economic growth by working with industry to develop and apply - technology, measurements, and standards. Has primary Government - responsibility for INFOSEC standards for unclassified but - sensitive information. (See: ANSI, DES, DSA, DSS, FIPS, NIAP, - NSA.) - - $ National Security Agency (NSA) - (N) A U.S. Department of Defense intelligence agency that has - primary Government responsibility for INFOSEC for classified - information and for unclassified but sensitive information handled - by national security systems. (See: FORTEZZA, KEA, MISSI, NIAP, - NIST, SKIPJACK.) - - $ need-to-know - (I) The necessity for access to, knowledge of, or possession of - specific information required to carry out official duties. - - (C) This criterion is used in security procedures that require a - custodian of sensitive information, prior to disclosing the - information to someone else, to establish that the intended - recipient has proper authorization to access the information. - - $ network - See: computer network. - - $ NIAP - See: National Information Assurance Partnership. - - $ NIST - See: National Institute of Standards and Technology. - - $ NLSP - Network Layer Security Protocol. An OSI protocol (IS0 11577) for - end-to-end encryption services at the top of OSI layer 3. NLSP is - derived from an SDNS protocol, SP3, but is much more complex. - - - -Shirey Informational [Page 111] - -RFC 2828 Internet Security Glossary May 2000 - - - $ no-lone zone - (I) A room or other space to which no person may have - unaccompanied access and that, when occupied, is required to be - occupied by two or more appropriately authorized persons. (See: - dual control.) - - $ nonce - (I) A random or non-repeating value that is included in data - exchanged by a protocol, usually for the purpose of guaranteeing - liveness and thus detecting and protecting against replay attacks. - - $ non-critical - See: critical (extension of certificate). - - $ non-repudiation service - (I) A security service that provide protection against false - denial of involvement in a communication. (See: repudiation.) - - (C) Non-repudiation service does not and cannot prevent an entity - from repudiating a communication. Instead, the service provides - evidence that can be stored and later presented to a third party - to resolve disputes that arise if and when a communication is - repudiated by one of the entities involved. There are two basic - kinds of non-repudiation service: - - - "Non-repudiation with proof of origin" provides the recipient - of data with evidence that proves the origin of the data, and - thus protects the recipient against an attempt by the - originator to falsely deny sending the data. This service can - be viewed as a stronger version of an data origin - authentication service, in that it proves authenticity to a - third party. - - - "Non-repudiation with proof of receipt" provides the originator - of data with evidence that proves the data was received as - addressed, and thus protects the originator against an attempt - by the recipient to falsely deny receiving the data. - - (C) Phases of a Non-Repudiation Service: Ford [For94, For97] uses - the term "critical action" to refer to the act of communication - that is the subject of the service: - - - - - - - - - - -Shirey Informational [Page 112] - -RFC 2828 Internet Security Glossary May 2000 - - - -------- -------- -------- -------- -------- . -------- - Phase 1: Phase 2: Phase 3: Phase 4: Phase 5: . Phase 6: - Request Generate Transfer Verify Retain . Resolve - Service Evidence Evidence Evidence Evidence . Dispute - -------- -------- -------- -------- -------- . -------- - - Service Critical Evidence Evidence Archive . Evidence - Request => Action => Stored => Is => Evidence . Is - Is Made Occurs For Later Tested In Case . Verified - and Use | ^ Critical . ^ - Evidence v | Action Is . | - Is +-------------------+ Repudiated . | - Generated |Verifiable Evidence|------> ... . ----+ - +-------------------+ - - Phase / Explanation - ------------------- - 1. Before the critical action, the service requester asks, either - implicitly or explicitly, to have evidence of the action be - generated. - 2. When the critical action occurs, evidence is generated by a - process involving the potential repudiator and possibly also a - trusted third party. - 3. The evidence is transferred to the requester, or stored by a - third party, for later use if needed. - 4. The entity that holds the evidence tests to be sure that it - will suffice if a dispute arises. - 5. The evidence is retained for possible future retrieval and use. - 6. In this phase, which occurs only if the critical action is - repudiated, the evidence is retrieved from storage, presented, - and verified to resolve the dispute. - - $ no-PIN ORA (NORA) - (O) MISSI usage: An organizational RA that operates in a mode in - which the ORA performs no card management functions and, - therefore, does not require knowledge of either the SSO PIN or - user PIN for an end user's FORTEZZA PC card. - - $ NORA - See: no-PIN ORA. - - $ notarization - (I) Registration of data under the authority or in the care of a - trusted third party, thus making it possible to provide subsequent - assurance of the accuracy of characteristics claimed for the data, - such as content, origin, time, and delivery. [I7498 Part 2] (See: - digital notary.) - - - - -Shirey Informational [Page 113] - -RFC 2828 Internet Security Glossary May 2000 - - - $ NULL encryption algorithm - (I) An algorithm [R2410] that does nothing to transform plaintext - data; i.e., a no-op. It originated because of IPsec ESP, which - always specifies the use of an encryption algorithm to provide - confidentiality. The NULL encryption algorithm is a convenient way - to represent the option of not applying encryption in ESP (or in - any other context where this is needed). - - $ OAKLEY - (I) A key establishment protocol (proposed for IPsec but - superseded by IKE) based on the Diffie-Hellman algorithm and - designed to be a compatible component of ISAKMP. [R2412] - - (C) OAKLEY establishes a shared key with an assigned identifier - and associated authenticated identities for parties. I.e., OAKLEY - provides authentication service to ensure the entities of each - other's identity, even if the Diffie-Hellman exchange is - threatened by active wiretapping. Also, provides public-key - forward secrecy for the shared key and supports key updates, - incorporation of keys distributed by out-of-band mechanisms, and - user-defined abstract group structures for use with Diffie- - Hellman. - - $ object - (I) Trusted computer system modeling usage: A system element that - contains or receives information. (See: Bell-LaPadula Model, - trusted computer system.) - - $ object identifier (OID) - (I) An official, globally unique name for a thing, written as a - sequence of integers (which are formed and assigned as defined in - the ASN.1 standard) and used to reference the thing in abstract - specifications and during negotiation of security services in a - protocol. - - (O) "A value (distinguishable from all other such values) which is - associated with an object." [X680] - - (C) Objects named by OIDs are leaves of the object identifier tree - (which is similar to but different from the X.500 Directory - Information Tree). Each arc (i.e., each branch of the tree) is - labeled with a non-negative integer. An OID is the sequence of - integers on the path leading from the root of the tree to a named - object. - - (C) The OID tree has three arcs immediately below the root: {0} - for use by ITU-T, {1} for use by ISO, and {2} for use by both - jointly. Below ITU-T are four arcs, where {0 0} is for ITU-T - - - -Shirey Informational [Page 114] - -RFC 2828 Internet Security Glossary May 2000 - - - recommendations. Below {0 0} are 26 arcs, one for each series of - recommendations starting with the letters A to Z, and below these - are arcs for each recommendation. Thus, the OID for ITU-T - Recommendation X.509 is {0 0 24 509}. Below ISO are four arcs, - where {1 0 }is for ISO standards, and below these are arcs for - each ISO standard. Thus, the OID for ISO/IEC 9594-8 (the ISO - number for X.509) is {1 0 9594 8}. - - (C) The following are additional examples: ANSI registers - organization names below the branch {joint-iso-ccitt(2) - country(16) US(840) organization(1)}. The NIST CSOR records PKI - objects below the branch {joint-iso-ccitt(2) country(16) us(840) - gov(101) csor(3) pki(4)}. The U.S. Department of Defense registers - INFOSEC objects below the branch {joint-iso-ccitt(2) country(16) - us(840) organization(1) gov(101) dod(2) infosec(1)}. The OID for - the PKIX private extension is defined in an arc below the arc for - the PKIX name space, as {iso(1) identified-organization(3) dod(6) - internet(1) security(5) mechanisms(5) pkix(7) 1 1}. - - $ object reuse - (N) "The reassignment and reuse of a storage medium (e.g., page - frame, disk sector, magnetic tape) that once contained one or more - [information] objects. To be securely reused and assigned to a new - subject, storage media must contain no residual data (magnetic - remanence) from the object(s) previously contained in the media." - [NCS04] - - $ OCSP - See: On-line Certificate Status Protocol. - - $ octet - (I) A data unit of eight bits. (See: byte.) - - (c) This term is used in networking (especially in OSI standards) - in preference to "byte", because some systems use "byte" for data - storage units of a size other than eight. - - $ OFB - See: output feedback. - - $ ohnosecond - (C) That minuscule fraction of time in which you realize that your - private key has been compromised. - - $ OID - See: object identifier. - - - - - -Shirey Informational [Page 115] - -RFC 2828 Internet Security Glossary May 2000 - - - $ On-line Certificate Status Protocol (OCSP) - (I) An Internet protocol used by a client to obtain from a server - the validity status and other information concerning a digital - certificate. - - (C) In some applications, such as those involving high-value - commercial transactions, it may be necessary to obtain certificate - revocation status that is more timely than is possible with CRLs - or to obtain other kinds of status information. OCSP may be used - to determine the current revocation status of a digital - certificate, in lieu of or as a supplement to checking against a - periodic CRL. An OCSP client issues a status request to an OCSP - server and suspends acceptance of the certificate in question - until the server provides a response. - - $ one-time pad - (I) An encryption algorithm in which the key is a random sequence - of symbols and each symbol is used for encryption only one time-- - to encrypt only one plaintext symbol to produce only one - ciphertext symbol--and a copy of the key is used similarly for - decryption. - - (C) To ensure one-time use, the copy of the key used for - encryption is destroyed after use, as is the copy used for - decryption. This is the only encryption algorithm that is truly - unbreakable, even given unlimited resources for cryptanalysis - [Schn], but key management costs and synchronization problems make - it impractical except in special situations. - - $ one-time password - $ One-Time Password (OTP) - 1. Not capitalized: A "one-time password" is a simple - authentication technique in which each password is used only once - as authentication information that verifies an identity. This - technique counters the threat of a replay attack that uses - passwords captured by wiretapping. - - 2. Capitalized: "One-Time Password" is an Internet protocol - [R1938] that is based on S/KEY and uses a cryptographic hash - function to generate one-time passwords for use as authentication - information in system login and in other processes that need - protection against replay attacks. - - $ one-way encryption - (I) Irreversible transformation of plaintext to ciphertext, such - that the plaintext cannot be recovered from the ciphertext by - other than exhaustive procedures even if the cryptographic key is - known. (See: encryption.) - - - -Shirey Informational [Page 116] - -RFC 2828 Internet Security Glossary May 2000 - - - $ one-way function - (I) "A (mathematical) function, f, which is easy to compute, but - which for a general value y in the range, it is computationally - difficult to find a value x in the domain such that f(x) = y. - There may be a few values of y for which finding x is not - computationally difficult." [X509] - - (D) ISDs SHOULD NOT use this term as a synonym for "cryptographic - hash". - - $ open security environment - (O) U.S. Department of Defense usage: A system environment that - meets at least one of the following conditions: (a) Application - developers (including maintainers) do not have sufficient - clearance or authorization to provide an acceptable presumption - that they have not introduced malicious logic. (b) Configuration - control does not provide sufficient assurance that applications - and the equipment are protected against the introduction of - malicious logic prior to and during the operation of system - applications. [NCS04] (See: closed security environment.) - - $ Open Systems Interconnection (OSI) Reference Model (OSIRM) - (N) A joint ISO/ITU-T standard [I7498 Part 1] for a seven-layer, - architectural communication framework for interconnection of - computers in networks. - - (C) OSI-based standards include communication protocols that are - mostly incompatible with the Internet Protocol Suite, but also - include security models, such as X.509, that are used in the - Internet. - - (C) The OSIRM layers, from highest to lowest, are (7) Application, - (6) Presentation, (5) Session, (4) Transport, (3) Network, (2) - Data Link, and (1) Physical. In this Glossary, these layers are - referred to by number to avoid confusing them with Internet - Protocol Suite layers, which are referred to by name. - - (C) Some unknown person described how the OSI layers correspond to - the seven deadly sins: - - 7. Wrath: Application is always angry at the mess it sees below - itself. (Hey! Who is it to be pointing fingers?) - 6. Sloth: Presentation is too lazy to do anything productive by - itself. - 5. Lust: Session is always craving and demanding what truly - belongs to Application's functionality. - 4. Avarice: Transport wants all of the end-to-end functionality. - (Of course, it deserves it, but life isn't fair.) - - - -Shirey Informational [Page 117] - -RFC 2828 Internet Security Glossary May 2000 - - - 3. Gluttony: (Connection-Oriented) Network is overweight and - overbearing after trying too often to eat Transport's lunch. - 2. Envy: Poor Data Link is always starved for attention. (With - Asynchronous Transfer Mode, maybe now it is feeling less - neglected.) - 1. Pride: Physical has managed to avoid much of the controversy, - and nearly all of the embarrassment, suffered by the others. - - (C) John G. Fletcher described how the OSI layers also correspond - to Snow White's dwarf friends: - - 7. Doc: Application acts as if it is in charge, but sometimes - muddles its syntax. - 6. Sleepy: Presentation is indolent, being guilty of the sin of - Sloth. - 5. Dopey: Session is confused because its charter is not very - clear. - 4. Grumpy: Transport is irritated because Network has encroached - on Transport's turf. - 3. Happy: Network smiles for the same reason that Transport is - irritated. - 2. Sneezy: Data Link makes loud noises in the hope of attracting - attention. - 1. Bashful: Physical quietly does its work, unnoticed by the - others. - - $ operational integrity - (I) A synonym for "system integrity"; emphasizes the actual - performance of system functions rather than just the ability to - perform them. - - $ operations security (OPSEC) - (I) A process to identify, control, and protect evidence of the - planning and execution of sensitive activities and operations, and - thereby prevent potential adversaries from gaining knowledge of - capabilities and intentions. - - $ OPSEC - See: operations security. - - $ ORA - See: organizational registration authority. - - $ Orange Book - (D) ISDs SHOULD NOT use this term as a synonym for "Trusted - Computer System Evaluation Criteria" [CSC001, DOD1]. Instead, use - - - - - -Shirey Informational [Page 118] - -RFC 2828 Internet Security Glossary May 2000 - - - the full, proper name of the document or, in subsequent - references, the abbreviation "TCSEC". (See: (usage note under) - Green Book.) - - $ organizational certificate - (O) MISSI usage: A type of MISSI X.509 public-key certificate that - is issued to support organizational message handling for the U.S. - Government's Defense Message System. - - $ organizational registration authority (ORA) - (I) General usage: An RA for an organization. - - (O) MISSI usage: The MISSI implementation of RA. A MISSI end - entity that (a) assists a PCA, CA, or SCA to register other end - entities, by gathering, verifying, and entering data and - forwarding it to the signing authority and (b) may also assist - with card management functions. An ORA is a local administrative - authority, and the term refers both to the office or role, and to - the person who fills that office. An ORA does not sign - certificates, CRLs, or CKLs. (See: no-PIN ORA, SSO-PIN ORA, user- - PIN ORA.) - - $ origin authentication - $ origin authenticity - (D) ISDs SHOULD NOT use these terms because they look like - careless use of an internationally standardized term. Instead, use - "data origin authentication" or "peer entity authentication", - depending which is meant. - - $ OSI - $ OSIRM - See: Open Systems Interconnection Reference Model. - - $ OTP - See: One-Time Password. - - $ out of band - (I) Transfer of information using a channel that is outside (i.e., - separate from) the channel that is normally used. (See: covert - channel.) - - (C) Out-of-band mechanisms are often used to distribute shared - secrets (e.g., a symmetric key) or other sensitive information - items (e.g., a root key) that are needed to initialize or - otherwise enable the operation of cryptography or other security - mechanisms. (See: key distribution.) - - - - - -Shirey Informational [Page 119] - -RFC 2828 Internet Security Glossary May 2000 - - - $ output feedback (OFB) - (N) A block cipher mode [FP081] that modifies electronic codebook - mode to operate on plaintext segments of variable length less than - or equal to the block length. - - (C) This mode operates by directly using the algorithm's - previously generated output block as the algorithm's next input - block (i.e., by "feeding back" the output block) and combining - (exclusive OR-ing) the output block with the next plaintext - segment (of block length or less) to form the next ciphertext - segment. - - $ outside attack - $ outsider attack - See: (secondary definition under) attack. - - $ P1363 - See: IEEE P1363. - - $ PAA - See: policy approving authority. - - $ packet filter - See: (secondary definition under) filtering router. - - $ pagejacking - (I) A contraction of "Web page hijacking". A masquerade attack in - which the attacker copies (steals) a home page or other material - from the target server, rehosts the page on a server the attacker - controls, and causes the rehosted page to be indexed by the major - Web search services, thereby diverting browsers from the target - server to the attacker's server. - - (D) ISDs SHOULD NOT use this term without including a definition, - because the term is not listed in most dictionaries and could - confuse international readers. (See: (usage note under) Green - Book.) - - $ PAN - See: primary account number. - - $ PAP - See: Password Authentication Protocol. - - - - - - - - -Shirey Informational [Page 120] - -RFC 2828 Internet Security Glossary May 2000 - - - $ partitioned security mode - (N) A mode of operation of an information system, wherein all - users have the clearance, but not necessarily formal access - authorization and need-to-know, for all information handled by the - system. This mode is defined in U.S. Department of Defense policy - regarding system accreditation. [DoD2] - - $ passive attack - See: (secondary definition under) attack. - - $ passive wiretapping - See: (secondary definition under) wiretapping. - - $ password - (I) A secret data value, usually a character string, that is used - as authentication information. (See: challenge-response.) - - (C) A password is usually matched with a user identifier that is - explicitly presented in the authentication process, but in some - cases the identity may be implicit. - - (C) Using a password as authentication information assumes that - the password is known only by the system entity whose identity is - being authenticated. Therefore, in a network environment where - wiretapping is possible, simple authentication that relies on - transmission of static (i.e., repetitively used) passwords as - cleartext is inadequate. (See: one-time password, strong - authentication.) - - $ Password Authentication Protocol (PAP) - (I) A simple authentication mechanism in PPP. In PAP, a user - identifier and password are transmitted in cleartext. [R1334] - (See: CHAP.) - - $ password sniffing - (I) Passive wiretapping, usually on a local area network, to gain - knowledge of passwords. (See: (usage note under) sniffing.) - - $ path discovery - (I) For a digital certificate, the process of finding a set of - public-key certificates that comprise a certification path from a - trusted key to that specific certificate. - - $ path validation - (I) The process of validating (a) all of the digital certificates - in a certification path and (b) the required relationships between - those certificates, thus validating the contents of the last - certificate on the path. (See: certificate validation.) - - - -Shirey Informational [Page 121] - -RFC 2828 Internet Security Glossary May 2000 - - - $ payment card - (N) SET usage: Collectively refers "to credit cards, debit cards, - charge cards, and bank cards issued by a financial institution and - which reflects a relationship between the cardholder and the - financial institution." [SET2] - - $ payment gateway - (O) SET usage: A system operated by an acquirer, or a third party - designated by an acquirer, for the purpose of providing electronic - commerce services to the merchants in support of the acquirer, and - which interfaces to the acquirer to support the authorization, - capture, and processing of merchant payment messages, including - payment instructions from cardholders. [SET1, SET2] - - $ payment gateway certification authority (SET PCA) - (O) SET usage: A CA that issues digital certificates to payment - gateways and is operated on behalf of a payment card brand, an - acquirer, or another party according to brand rules. A SET PCA - issues a CRL for compromised payment gateway certificates. [SET2] - (See: PCA.) - - $ PC card - (N) A type of credit card-sized, plug-in peripheral device that - was originally developed to provide memory expansion for portable - computers, but is also used for other kinds of functional - expansion. (See: FORTEZZA, PCMCIA.) - - (C) The international PC Card Standard defines a non-proprietary - form factor in three standard sizes--Types I, II and III--each of - which have a 68-pin interface between the card and the socket into - which it plugs. All three types have the same length and width, - roughly the size of a credit card, but differ in their thickness - from 3.3 to 10.5 mm. Examples include storage modules, modems, - device interface adapters, and cryptographic modules. - - $ PCA - (D) ISDs SHOULD NOT use this acronym without a qualifying - adjective because that would be ambiguous. (See: Internet policy - certification authority, (MISSI) policy creation authority, (SET) - payment gateway certification authority.) - - $ PCMCIA - (N) Personal Computer Memory Card International Association, a - group of manufacturers, developers, and vendors, founded in 1989 - to standardize plug-in peripheral memory cards for personal - computers and now extended to deal with any technology that works - in the PC card form factor. (See: PC card.) - - - - -Shirey Informational [Page 122] - -RFC 2828 Internet Security Glossary May 2000 - - - $ peer entity authentication - (I) "The corroboration that a peer entity in an association is the - one claimed." [I7498 Part 2] (See: authentication.) - - $ peer entity authentication service - (I) A security service that verifies an identity claimed by or for - a system entity in an association. (See: authentication, - authentication service.) - - (C) This service is used at the establishment of, or at times - during, an association to confirm the identity of one entity to - another, thus protecting against a masquerade by the first entity. - However, unlike data origin authentication service, this service - requires an association to exist between the two entities, and the - corroboration provided by the service is valid only at the current - time that the service is provided. - - (C) See: "relationship between data integrity service and - authentication services" under data integrity service. - - $ PEM - See: Privacy Enhanced Mail. - - $ penetration - (I) Successful, repeatable, unauthorized access to a protected - system resource. (See: attack, violation.) - - $ penetration test - (I) A system test, often part of system certification, in which - evaluators attempt to circumvent the security features of the - system. [NCS04] - - (C) Penetration testing may be performed under various constraints - and conditions. However, for a TCSEC evaluation, testers are - assumed to have all system design and implementation - documentation, including source code, manuals, and circuit - diagrams, and to work under no greater constraints than those - applied to ordinary users. - - $ perfect forward secrecy - See: (discussion under) public-key forward secrecy. - - $ perimeter - See: security perimeter. - - - - - - - -Shirey Informational [Page 123] - -RFC 2828 Internet Security Glossary May 2000 - - - $ periods processing - (I) A mode of system operation in which information of different - sensitivities is processed at distinctly different times by the - same system, with the system being properly purged or sanitized - between periods. (See: color change.) - - $ permission - (I) A synonym for "authorization", but "authorization" is - preferred in the PKI context. (See: privilege.) - - $ personal identification number (PIN) - (I) A character string used as a password to gain access to a - system resource. (See: authentication information.) - - (C) Despite the words "identification" and "number", a PIN seldom - serves as a user identifier, and a PIN's characters are not - necessarily all numeric. A better name for this concept would have - been "personal authentication system string (PASS)". - - (C) Retail banking applications commonly use 4-digit PINs. - FORTEZZA PC card's use up to 12 characters for user or SSO PINs. - - $ personality - $ personality label - (O) MISSI usage: A set of MISSI X.509 public-key certificates that - have the same subject DN, together with their associated private - keys and usage specifications, that is stored on a FORTEZZA PC - card to support a role played by the card's user. - - (C) When a card's user selects a personality to use in a FORTEZZA- - aware application, the data determines behavior traits (the - personality) of the application. A card's user may have multiple - personalities on the card. Each has a "personality label", a user- - friendly character string that applications can display to the - user for selecting or changing the personality to be used. For - example, a military user's card might contain three personalities: - GENERAL HALFTRACK, COMMANDER FORT SWAMPY, and NEW YEAR'S EVE PARTY - CHAIRMAN. Each personality includes one or more certificates of - different types (such as DSA versus RSA), for different purposes - (such as digital signature versus encryption), or with different - authorizations. - - $ personnel security - (I) Procedures to ensure that persons who access a system have - proper clearance, authorization, and need-to-know as required by - the system's security policy. - - - - - -Shirey Informational [Page 124] - -RFC 2828 Internet Security Glossary May 2000 - - - $ PGP(trademark) - See: Pretty Good Privacy. - - $ Photuris - (I) A UDP-based, key establishment protocol for session keys, - designed for use with the IPsec protocols AH and ESP. Superseded - by IKE. - - $ phreaking - (I) A contraction of "telephone breaking". An attack on or - penetration of a telephone system or, by extension, any other - communication or information system. [Raym] - - (D) ISDs SHOULD NOT use this term because it is not listed in most - dictionaries and could confuse international readers. - - $ physical security - (I) Tangible means of preventing unauthorized physical access to a - system. E.g., fences, walls, and other barriers; locks, safes, and - vaults; dogs and armed guards; sensors and alarm bells. [FP031, - R1455] - - $ piggyback attack - (I) A form of active wiretapping in which the attacker gains - access to a system via intervals of inactivity in another user's - legitimate communication connection. Sometimes called a "between- - the-lines" attack. (See: hijack attack, man-in-the-middle attack.) - - $ PIN - See: personal identification number. - - $ ping of death - (I) An attack that sends an improperly large ICMP [R0792] echo - request packet (a "ping") with the intent of overflowing the input - buffers of the destination machine and causing it to crash. - - $ ping sweep - (I) An attack that sends ICMP [R0792] echo requests ("pings") to a - range of IP addresses, with the goal of finding hosts that can be - probed for vulnerabilities. - - $ PKCS - See: Public-Key Cryptography Standards. - - $ PKCS #7 - (N) A standard [PKC07, R2315] from the PKCS series; defines a - syntax for data that may have cryptography applied to it, such as - for digital signatures and digital envelopes. - - - -Shirey Informational [Page 125] - -RFC 2828 Internet Security Glossary May 2000 - - - $ PKCS #10 - (N) A standard [PKC10] from the PKCS series; defines a syntax for - requests for public-key certificates. (See: certification - request.) - - (C) A PKCS #10 request contains a DN and a public key, and may - contain other attributes, and is signed by the entity making the - request. The request is sent to a CA, who converts it to an X.509 - public-key certificate (or some other form) and returns it, - possibly in PKCS #7 format. - - $ PKCS #11 - (N) A standard [PKC11] from the PKCS series; defines a software - CAPI called Cryptoki (pronounced "crypto-key"; short for - "cryptographic token interface") for devices that hold - cryptographic information and perform cryptographic functions. - - $ PKI - See: public-key infrastructure. - - $ PKIX - (I) (1.) A contraction of "Public-Key Infrastructure (X.509)", the - name of the IETF working group that is specifying an architecture - and set of protocols needed to support an X.509-based PKI for the - Internet. (2.) A collective name for that architecture and set of - protocols. - - (C) The goal of PKIX is to facilitate the use of X.509 public-key - certificates in multiple Internet applications and to promote - interoperability between different implementations that use those - certificates. The resulting PKI is intended to provide a framework - that supports a range of trust and hierarchy environments and a - range of usage environments. PKIX specifies (a) profiles of the v3 - X.509 public-key certificate standards and the v2 X.509 CRL - standards for the Internet; (b) operational protocols used by - relying parties to obtain information such as certificates or - certificate status; (c) management protocols used by system - entities to exchange information needed for proper management of - the PKI; and (d) information about certificate policies and CPSs, - covering the areas of PKI security not directly addressed in the - rest of PKIX. - - $ PKIX private extension - (I) PKIX defines a private extension to identify an on-line - verification service supporting the issuing CA. - - - - - - -Shirey Informational [Page 126] - -RFC 2828 Internet Security Glossary May 2000 - - - $ plaintext - (I) Data that is input to and transformed by an encryption - process, or that is output by a decryption process. - - (C) Usually, the plaintext input to an encryption operation is - cleartext. But in some cases, the input is ciphertext that was - output from another encryption operation. (See: superencryption.) - - $ Point-to-Point Protocol (PPP) - (I) An Internet Standard protocol [R1661] for encapsulation and - full-duplex transportation of network layer (mainly OSI layer 3) - protocol data packets over a link between two peers, and for - multiplexing different network layer protocols over the same link. - Includes optional negotiation to select and use a peer entity - authentication protocol to authenticate the peers to each other - before they exchange network layer data. (See: CHAP, EAP, PAP.) - - $ Point-to-Point Tunneling Protocol (PPTP) - (I) An Internet client-server protocol (originally developed by - Ascend and Microsoft) that enables a dial-up user to create a - virtual extension of the dial-up link across a network by - tunneling PPP over IP. (See: L2TP.) - - (C) PPP can encapsulate any Internet Protocol Suite network layer - protocol (or OSI layer 3 protocol). Therefore, PPTP does not - specify security services; it depends on protocols above and below - it to provide any needed security. PPTP makes it possible to - divorce the location of the initial dial-up server (i.e., the PPTP - Access Concentrator, the client, which runs on a special-purpose - host) from the location at which the dial-up protocol (PPP) - connection is terminated and access to the network is provided - (i.e., the PPTP Network Server, which runs on a general-purpose - host). - - $ policy - (D) ISDs SHOULD NOT use this word as an abbreviation for either - "security policy" or "certificate policy". Instead, to avoid - misunderstanding, use the fully qualified term, at least at the - point of first usage. - - $ policy approving authority (PAA) - (O) MISSI usage: The top-level signing authority of a MISSI - certification hierarchy. The term refers both to that - authoritative office or role and to the person who plays that - role. (See: root registry.) - - - - - - -Shirey Informational [Page 127] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) A PAA registers MISSI PCAs and signs their X.509 public-key - certificates. A PAA issues CRLs but does not issue a CKL. A PAA - may issue cross-certificates to other PAAs. - - $ policy certification authority (Internet PCA) - (I) An X.509-compliant CA at the second level of the Internet - certification hierarchy, under the Internet Policy Registration - Authority (IPRA). Each PCA operates in accordance with its - published security policy (see: certification practice statement) - and within constraints established by the IPRA for all PCAs. - [R1422]. (See: policy creation authority.) - - $ policy creation authority (MISSI PCA) - (O) MISSI usage: The second level of a MISSI certification - hierarchy; the administrative root of a security policy domain of - MISSI users and other, subsidiary authorities. The term refers - both to that authoritative office or role and to the person who - fills that office. (See: policy certification authority.) - - (C) A MISSI PCA's certificate is issued by a policy approving - authority. The PCA registers the CAs in its domain, defines their - configurations, and issues their X.509 public-key certificates. - (The PCA may also issue certificates for SCAs, ORAs, and other end - entities, but a PCA does not usually do this.) The PCA - periodically issues CRLs and CKLs for its domain. - - $ Policy Management Authority - (N) Canadian usage: An organization responsible for PKI oversight - and policy management in the Government of Canada. - - $ policy mapping - (I) "Recognizing that, when a CA in one domain certifies a CA in - another domain, a particular certificate policy in the second - domain may be considered by the authority of the first domain to - be equivalent (but not necessarily identical in all respects) to a - particular certificate policy in the first domain." [X509] - - $ POP3 - See: Post Office Protocol, version 3. - - $ POP3 APOP - (I) A POP3 "command" (better described as a transaction type, or a - protocol-within-a-protocol) by which a POP3 client optionally uses - a keyed hash (based on MD5) to authenticate itself to a POP3 - server and, depending on the server implementation, to protect - against replay attacks. (See: CRAM, POP3 AUTH, IMAP4 - AUTHENTICATE.) - - - - -Shirey Informational [Page 128] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) The server includes a unique timestamp in its greeting to the - client. The subsequent APOP command sent by the client to the - server contains the client's name and the hash result of applying - MD5 to a string formed from both the timestamp and a shared secret - that is known only to the client and the server. APOP was designed - to provide as an alternative to using POP3's USER and PASS (i.e., - password) command pair, in which the client sends a cleartext - password to the server. - - $ POP3 AUTH - (I) A "command" [R1734] (better described as a transaction type, - or a protocol-within-a-protocol) in POP3, by which a POP3 client - optionally proposes a mechanism to a POP3 server to authenticate - the client to the server and provide other security services. - (See: POP3 APOP, IMAP4 AUTHENTICATE.) - - (C) If the server accepts the proposal, the command is followed by - performing a challenge-response authentication protocol and, - optionally, negotiating a protection mechanism for subsequent POP3 - interactions. The security mechanisms used by POP3 AUTH are those - used by IMAP4. - - $ port scan - (I) An attack that sends client requests to a range of server port - addresses on a host, with the goal of finding an active port and - exploiting a known vulnerability of that service. - - $ POSIX - (N) Portable Operating System Interface for Computer Environments, - a standard [FP151, IS9945-1] (originally IEEE Standard P1003.1) - that defines an operating system interface and environment to - support application portability at the source code level. It is - intended to be used by both application developers and system - implementers. - - (C) P1003.1 supports security functionality like those on most - UNIX systems, including discretionary access control and - privilege. IEEE Draft Standard P1003.6.1 specifies additional - functionality not provided in the base standard, including (a) - discretionary access control, (b) audit trail mechanisms, (c) - privilege mechanisms, (d) mandatory access control, and (e) - information label mechanisms. - - $ Post Office Protocol, version 3 (POP3) - (I) An Internet Standard protocol [R1939] by which a client - workstation can dynamically access a mailbox on a server host to - retrieve mail messages that the server has received and is holding - for the client. (See: IMAP4.) - - - -Shirey Informational [Page 129] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) POP3 has mechanisms for optionally authenticating a client to - a server and providing other security services. (See: POP3 APOP, - POP3 AUTH.) - - $ PPP - See: Point-to-Point Protocol. - - $ PPTP - See: Point-to-Point Tunneling Protocol. - - $ pre-authorization - (I) A capability of a CAW that enables certification requests to - be automatically validated against data provided in advance to the - CA by an authorizing entity. - - $ Pretty Good Privacy(trademark) (PGP(trademark)) - (O) Trademarks of Network Associates, Inc., referring to a - computer program (and related protocols) that uses cryptography to - provide data security for electronic mail and other applications - on the Internet. (See: MOSS, PEM, S/MIME.) - - (C) PGP encrypts messages with IDEA in CFB mode, distributes the - IDEA keys by encrypting them with RSA, and creates digital - signatures on messages with MD5 and RSA. To establish ownership of - public keys, PGP depends on the web of trust. (See: Privacy - Enhanced Mail.) - - $ primary account number (PAN) - (O) SET usage: "The assigned number that identifies the card - issuer and cardholder. This account number is composed of an - issuer identification number, an individual account number - identification, and an accompanying check digit as defined by ISO - 7812-1985." [SET2, IS7812] (See: bank identification number.) - - (C) The PAN is embossed, encoded, or both on a magnetic-strip- - based credit card. The PAN identifies the issuer to which a - transaction is to be routed and the account to which it is to be - applied unless specific instructions indicate otherwise. The - authority that assigns the bank identification number part of the - PAN is the American Bankers Association. - - $ privacy - (I) The right of an entity (normally a person), acting in its own - behalf, to determine the degree to which it will interact with its - environment, including the degree to which the entity is willing - to share information about itself with others. (See: anonymity.) - - - - - -Shirey Informational [Page 130] - -RFC 2828 Internet Security Glossary May 2000 - - - (O) "The right of individuals to control or influence what - information related to them may be collected and stored and by - whom and to whom that information may be disclosed." [I7498 Part - 2] - - (D) ISDs SHOULD NOT use this term as a synonym for "data - confidentiality" or "data confidentiality service", which are - different concepts. Privacy is a reason for security rather than a - kind of security. For example, a system that stores personal data - needs to protect the data to prevent harm, embarrassment, - inconvenience, or unfairness to any person about whom data is - maintained, and to protect the person's privacy. For that reason, - the system may need to provide data confidentiality service. - - $ Privacy Enhanced Mail (PEM) - (I) An Internet protocol to provide data confidentiality, data - integrity, and data origin authentication for electronic mail. - [R1421, R1422]. (See: MOSS, MSP, PGP, S/MIME.) - - (C) PEM encrypts messages with DES in CBC mode, provides key - distribution of DES keys by encrypting them with RSA, and signs - messages with RSA over either MD2 or MD5. To establish ownership - of public keys, PEM uses a certification hierarchy, with X.509 - public-key certificates and X.509 CRLs that are signed with RSA - and MD2. (See: Pretty Good Privacy.) - - (C) PEM is designed to be compatible with a wide range of key - management methods, but is limited to specifying security services - only for text messages and, like MOSS, has not been widely - implemented in the Internet. - - $ private component - (I) A synonym for "private key". - - (D) In most cases, ISDs SHOULD NOT use this term; to avoid - confusing readers, use "private key" instead. However, the term - MAY be used when specifically discussing a key pair; e.g., "A key - pair has a public component and a private component." - - $ private extension - See: (secondary definition under) extension. - - $ private key - (I) The secret component of a pair of cryptographic keys used for - asymmetric cryptography. (See: key pair, public key.) - - (O) "(In a public key cryptosystem) that key of a user's key pair - which is known only by that user." [X509] - - - -Shirey Informational [Page 131] - -RFC 2828 Internet Security Glossary May 2000 - - - $ privilege - (I) An authorization or set of authorizations to perform security- - relevant functions, especially in the context of a computer - operating system. - - $ privilege management infrastructure - (N) "The complete set of processes required to provide an - authorization service", i.e., processes concerned with attribute - certificates. [FPDAM] (See: PKI.) - - (D) ISDs SHOULD NOT use this term and its definition because the - definition is vague, and there is no consensus on an alternate - definition. - - $ privileged process - (I) An computer process that is authorized (and, therefore, - trusted) to perform some security-relevant functions that ordinary - processes are not. (See: privilege, trusted process.) - - $ procedural security - (D) ISDs SHOULD NOT use this term as a synonym for "administrative - security". Any type of security may involve procedures; therefore, - the term may be misleading. Instead, use "administrative - security", "communication security", "computer security", - "emanations security", "personnel security", "physical security", - or whatever specific type is meant. (See: security architecture.) - - $ proprietary - (I) Refers to information (or other property) that is owned by an - individual or organization and for which the use is restricted by - that entity. - - $ protected checksum - (I) A checksum that is computed for a data object by means that - protect against active attacks that would attempt to change the - checksum to make it match changes made to the data object. (See: - digital signature, keyed hash, (discussion under) checksum. - - $ protected distribution system - (I) A wireline or fiber-optic system that includes sufficient - safeguards (acoustic, electric, electromagnetic, and physical) to - permit its use for unencrypted transmission of (cleartext) data. - - $ protection authority - See: (secondary definition under) Internet Protocol Security - Option. - - - - - -Shirey Informational [Page 132] - -RFC 2828 Internet Security Glossary May 2000 - - - $ protection ring - (I) One of a hierarchy of privileged operation modes of a system - that gives certain access rights to processes authorized to - operate in that mode. - - $ protocol - (I) A set of rules (i.e., formats and procedures) to implement and - control some type of association (e.g., communication) between - systems. (E.g., see: Internet Protocol.) - - (C) In particular, a series of ordered steps involving computing - and communication that are performed by two or more system - entities to achieve a joint objective. [A9042] - - $ protocol suite - (I) A complementary collection of communication protocols used in - a computer network. (See: Internet, OSI.) - - $ proxy server - (I) A computer process--often used as, or as part of, a firewall-- - that relays a protocol between client and server computer systems, - by appearing to the client to be the server and appearing to the - server to be the client. (See: SOCKS.) - - (C) In a firewall, a proxy server usually runs on a bastion host, - which may support proxies for several protocols (e.g., FTP, HTTP, - and TELNET). Instead of a client in the protected enclave - connecting directly to an external server, the internal client - connects to the proxy server which in turn connects to the - external server. The proxy server waits for a request from inside - the firewall, forwards the request to the remote server outside - the firewall, gets the response, then sends the response back to - the client. The proxy may be transparent to the clients, or they - may need to connect first to the proxy server, and then use that - association to also initiate a connection to the real server. - - (C) Proxies are generally preferred over SOCKS for their ability - to perform caching, high-level logging, and access control. A - proxy can provide security service beyond that which is normally - part of the relayed protocol, such as access control based on peer - entity authentication of clients, or peer entity authentication of - servers when clients do not have that capability. A proxy at OSI - layer 7 can also provide finer-grained security service than can a - filtering router at OSI layer 3. For example, an FTP proxy could - permit transfers out of, but not into, a protected network. - - - - - - -Shirey Informational [Page 133] - -RFC 2828 Internet Security Glossary May 2000 - - - $ pseudo-random - (I) A sequence of values that appears to be random (i.e., - unpredictable) but is actually generated by a deterministic - algorithm. (See: random.) - - $ pseudo-random number generator - (I) A process used to deterministically generate a series of - numbers (usually integers) that appear to be random according to - certain statistical tests, but actually are pseudo-random. - - (C) Pseudo-random number generators are usually implemented in - software. - - $ public component - (I) A synonym for "public key". - - (D) In most cases, ISDs SHOULD NOT use this term; to avoid - confusing readers, use "private key" instead. However, the term - MAY be used when specifically discussing a key pair; e.g., "A key - pair has a public component and a private component." - - $ public key - (I) The publicly-disclosable component of a pair of cryptographic - keys used for asymmetric cryptography. (See: key pair, private - key.) - - (O) "(In a public key cryptosystem) that key of a user's key pair - which is publicly known." [X509] - - $ public-key certificate - (I) A digital certificate that binds a system entity's identity to - a public key value, and possibly to additional data items; a - digitally-signed data structure that attests to the ownership of a - public key. (See: X.509 public-key certificate.) - - (C) The digital signature on a public-key certificate is - unforgeable. Thus, the certificate can be published, such as by - posting it in a directory, without the directory having to protect - the certificate's data integrity. - - (O) "The public key of a user, together with some other - information, rendered unforgeable by encipherment with the private - key of the certification authority which issued it." [X509] - - $ public-key cryptography - (I) The popular synonym for "asymmetric cryptography". - - - - - -Shirey Informational [Page 134] - -RFC 2828 Internet Security Glossary May 2000 - - - $ Public-Key Cryptography Standards (PKCS) - (I) A series of specifications published by RSA Laboratories for - data structures and algorithm usage for basic applications of - asymmetric cryptography. (See: PKCS #7, PKCS #10, PKCS #11.) - - (C) The PKCS were begun in 1991 in cooperation with industry and - academia, originally including Apple, Digital, Lotus, Microsoft, - Northern Telecom, Sun, and MIT. Today, the specifications are - widely used, but they are not sanctioned by an official standards - organization, such as ANSI, ITU-T, or IETF. RSA Laboratories - retains sole decision-making authority over the PKCS. - - $ public-key forward secrecy (PFS) - (I) For a key agreement protocol based on asymmetric cryptography, - the property that ensures that a session key derived from a set of - long-term public and private keys will not be compromised if one - of the private keys is compromised in the future. - - (C) Some existing RFCs use the term "perfect forward secrecy" but - either do not define it or do not define it precisely. While - preparing this Glossary, we tried to find a good definition for - that term, but found this to be a muddled area. Experts did not - agree. For all practical purposes, the literature defines "perfect - forward secrecy" by stating the Diffie-Hellman algorithm. The term - "public-key forward secrecy" (suggested by Hilarie Orman) and the - "I" definition stated for it here were crafted to be compatible - with current Internet documents, yet be narrow and leave room for - improved terminology. - - (C) Challenge to the Internet security community: We need a - taxonomy--a family of mutually exclusive and collectively - exhaustive terms and definitions to cover the basic properties - discussed here--for the full range of cryptographic algorithms and - protocols used in Internet Standards: - - (C) Involvement of session keys vs. long-term keys: Experts - disagree about the basic ideas involved. - - - One concept of "forward secrecy" is that, given observations of - the operation of a key establishment protocol up to time t, and - given some of the session keys derived from those protocol runs, - you cannot derive unknown past session keys or future session - keys. - - - A related property is that, given observations of the protocol - and knowledge of the derived session keys, you cannot derive one - or more of the long-term private keys. - - - - -Shirey Informational [Page 135] - -RFC 2828 Internet Security Glossary May 2000 - - - - The "I" definition presented above involves a third concept of - "forward secrecy" that refers to the effect of the compromise of - long-term keys. - - - All three concepts involve the idea that a compromise of "this" - encryption key is not supposed to compromise the "next" one. There - also is the idea that compromise of a single key will compromise - only the data protected by the single key. In Internet literature, - the focus has been on protection against decryption of back - traffic in the event of a compromise of secret key material held - by one or both parties to a communication. - - (C) Forward vs. backward: Experts are unhappy with the word - "forward", because compromise of "this" encryption key also is not - supposed to compromise the "previous" one, which is "backward" - rather than forward. In S/KEY, if the key used at time t is - compromised, then all keys used prior to that are compromised. If - the "long-term" key (i.e., the base of the hashing scheme) is - compromised, then all keys past and future are compromised; thus, - you could say that S/KEY has neither forward nor backward secrecy. - - (C) Asymmetric cryptography vs. symmetric: Experts disagree about - forward secrecy in the context of symmetric cryptographic systems. - In the absence of asymmetric cryptography, compromise of any long- - term key seems to compromise any session key derived from the - long-term key. For example, Kerberos isn't forward secret, because - compromising a client's password (thus compromising the key shared - by the client and the authentication server) compromises future - session keys shared by the client and the ticket-granting server. - - (C) Ordinary forward secrecy vs. "perfect" forward secret: Experts - disagree about the difference between these two. Some say there is - no difference, and some say that the initial naming was - unfortunate and suggest dropping the word "perfect". Some suggest - using "forward secrecy" for the case where one long-term private - key is compromised, and adding "perfect" for when both private - keys (or, when the protocol is multi-party, all private keys) are - compromised. - - (C) Acknowledgements: Bill Burr, Burt Kaliski, Steve Kent, Paul - Van Oorschot, Michael Wiener, and, especially, Hilarie Orman - contributed ideas to this discussion. - - $ public-key infrastructure (PKI) - (I) A system of CAs (and, optionally, RAs and other supporting - servers and agents) that perform some set of certificate - management, archive management, key management, and token - - - - -Shirey Informational [Page 136] - -RFC 2828 Internet Security Glossary May 2000 - - - management functions for a community of users in an application of - asymmetric cryptography. (See: hierarchical PKI, mesh PKI, - security management infrastructure, trust-file PKI.) - - (O) PKIX usage: The set of hardware, software, people, policies, - and procedures needed to create, manage, store, distribute, and - revoke digital certificates based on asymmetric cryptography. - - (C) The core PKI functions are (a) to register users and issue - their public-key certificates, (b) to revoke certificates when - required, and (c) to archive data needed to validate certificates - at a much later time. Key pairs for data confidentiality may be - generated (and perhaps escrowed) by CAs or RAs, but requiring a - PKI client to generate its own digital signature key pair helps - maintain system integrity of the cryptographic system, because - then only the client ever possesses the private key it uses. Also, - an authority may be established to approve or coordinate CPSs, - which are security policies under which components of a PKI - operate. - - (C) A number of other servers and agents may support the core PKI, - and PKI clients may obtain services from them. The full range of - such services is not yet fully understood and is evolving, but - supporting roles may include archive agent, certified delivery - agent, confirmation agent, digital notary, directory, key escrow - agent, key generation agent, naming agent who ensures that issuers - and subjects have unique identifiers within the PKI, repository, - ticket-granting agent, and time stamp agent. - - $ RA - See: registration authority. - - $ RA domains - (I) A capability of a CAW that allows a CA to divide the - responsibility for certification requests among multiple RAs. - - (C) This capability might be used to restrict access to private - authorization data that is provided with a certification request, - and to distribute the responsibility to review and approve - certification requests in high volume environments. RA domains - might segregate certification requests according to an attribute - of the certificate subject, such as an organizational unit. - - $ RADIUS - See: Remote Authentication Dial-In User Service. - - - - - - -Shirey Informational [Page 137] - -RFC 2828 Internet Security Glossary May 2000 - - - $ Rainbow Series - (O) A set of more than 30 technical and policy documents with - colored covers, issued by the NCSC, that discuss in detail the - TCSEC and provide guidance for meeting and applying the criteria. - (See: Green Book, Orange Book, Red Book, Yellow Book.) - - $ random - (I) General usage: In mathematics, random means "unpredictable". A - sequence of values is called random if each successive value is - obtained merely by chance and does not depend on the preceding - values of the sequence, and a selected individual value is called - random if each of the values in the total population of - possibilities has equal probability of being selected. [Knuth] - (See: cryptographic key, pseudo-random, random number generator.) - - (I) Security usage: In cryptography and other security - applications, random means not only unpredictable, but also - "unguessable". When selecting data values to use for cryptographic - keys, "the requirement is for data that an adversary has a very - low probability of guessing or determining." It is not sufficient - to use data that "only meets traditional statistical tests for - randomness or which is based on limited range sources, such as - clocks. Frequently such random quantities are determinable [i.e., - guessable] by an adversary searching through an embarrassingly - small space of possibilities." [R1750] - - $ random number generator - (I) A process used to generate an unpredictable, uniformly - distributed series of numbers (usually integers). (See: pseudo- - random, random.) - - (C) True random number generators are hardware-based devices that - depend on the output of a "noisy diode" or other physical - phenomena. [R1750] - - $ RBAC - See: Role-Based Access Control. - - $ RC2 - $ RC4 - See: Rivest Cipher #2, Rivest Cipher #4. - - $ realm - (O) Kerberos usage: The domain of authority of a Kerberos server - (consisting of an authentication server and a ticket-granting - server), including the Kerberized clients and the Kerberized - application servers - - - - -Shirey Informational [Page 138] - -RFC 2828 Internet Security Glossary May 2000 - - - $ RED - (I) Designation for information system equipment or facilities - that handle (and for data that contains) only plaintext (or, - depending on the context, classified information), and for such - data itself. This term derives from U.S. Government COMSEC - terminology. (See: BLACK, RED/BLACK separation.) - - $ Red Book - (D) ISDs SHOULD NOT use this term as a synonym for "Trusted - Network Interpretation of the Trusted Computer System Evaluation - Criteria" [NCS05]. Instead, use the full proper name of the - document or, in subsequent references, a more conventional - abbreviation. (See: TCSEC, Rainbow Series, (usage note under) - Green Book.) - - $ RED/BLACK separation - (I) An architectural concept for cryptographic systems that - strictly separates the parts of a system that handle plaintext - (i.e., RED information) from the parts that handle ciphertext - (i.e., BLACK information). This term derives from U.S. Government - COMSEC terminology. (See: BLACK, RED.) - - $ reference monitor - (I) "An access control concept that refers to an abstract machine - that mediates all accesses to objects by subjects." [NCS04] (See: - security kernel.) - - (C) A reference monitor should be (a) complete (i.e., it mediates - every access), (b) isolated (i.e., it cannot be modified by other - system entities), and (c) verifiable (i.e., small enough to be - subjected to analysis and tests to ensure that it is correct). - - $ reflection attack - (I) A type of replay attack in which transmitted data is sent back - to its originator. - - $ register - $ registration - (I) An administrative act or process whereby an entity's name and - other attributes are established for the first time at a CA, prior - to the CA issuing a digital certificate that has the entity's name - as the subject. (See: registration authority.) - - (C) Registration may be accomplished either directly, by the CA, - or indirectly, by a separate RA. An entity is presented to the CA - or RA, and the authority either records the name(s) claimed for - the entity or assigns the entity's name(s). The authority also - determines and records other attributes of the entity that are to - - - -Shirey Informational [Page 139] - -RFC 2828 Internet Security Glossary May 2000 - - - be bound in a certificate (such as a public key or authorizations) - or maintained in the authority's database (such as street address - and telephone number). The authority is responsible, possibly - assisted by an RA, for authenticating the entity's identity and - verifying the correctness of the other attributes, in accordance - with the CA's CPS. - - (C) Among the registration issues that a CPS may address are the - following [R2527]: - - - How a claimed identity and other attributes are verified. - - How organization affiliation or representation is verified. - - What forms of names are permitted, such as X.500 DN, domain - name, or IP address. - - Whether names are required to be meaningful or unique, and - within what domain. - - How naming disputes are resolved, including the role of - trademarks. - - Whether certificates are issued to entities that are not - persons. - - Whether a person is required to appear before the CA or RA, or - can instead be represented by an agent. - - Whether and how an entity proves possession of the private key - matching a public key. - - $ registration authority (RA) - (I) An optional PKI entity (separate from the CAs) that does not - sign either digital certificates or CRLs but has responsibility - for recording or verifying some or all of the information - (particularly the identities of subjects) needed by a CA to issue - certificates and CRLs and to perform other certificate management - functions. (See: organizational registration authority, - registration.) - - (C) Sometimes, a CA may perform all certificate management - functions for all end users for which the CA signs certificates. - Other times, such as in a large or geographically dispersed - community, it may be necessary or desirable to offload secondary - CA functions and delegate them to an assistant, while the CA - retains the primary functions (signing certificates and CRLs). The - tasks that are delegated to an RA by a CA may include personal - authentication, name assignment, token distribution, revocation - reporting, key generation, and archiving. An RA is an optional PKI - component, separate from the CA, that is assigned secondary - functions. The duties assigned to RAs vary from case to case but - may include the following: - - - - - -Shirey Informational [Page 140] - -RFC 2828 Internet Security Glossary May 2000 - - - - Verifying a subject's identity, i.e., performing personal - authentication functions. - - Assigning a name to a subject. (See: distinguished name.) - - Verifying that a subject is entitled to have the attributes - requested for a certificate. - - Verifying that a subject possesses the private key that matches - the public key requested for a certificate. - - Performing functions beyond mere registration, such as - generating key pairs, distributing tokens, and handling - revocation reports. (Such functions may be assigned to a PKI - element that is separate from both the CA and the RA.) - - (I) PKIX usage: An optional PKI component, separate from the - CA(s). The functions that the RA performs will vary from case to - case but may include identity authentication and name assignment, - key generation and archiving of key pairs, token distribution, and - revocation reporting. [R2510] - - (O) SET usage: "An independent third-party organization that - processes payment card applications for multiple payment card - brands and forwards applications to the appropriate financial - institutions." [SET2] - - $ regrade - (I) Deliberately change the classification level of information in - an authorized manner. - - $ rekey - (I) Change the value of a cryptographic key that is being used in - an application of a cryptographic system. (See: certificate - rekey.) - - (C) For example, rekey is required at the end of a cryptoperiod or - key lifetime. - - $ reliability - (I) The ability of a system to perform a required function under - stated conditions for a specified period of time. (See: - availability, survivability.) - - $ relying party - (N) A synonym for "certificate user". Used in a legal context to - mean a recipient of a certificate who acts in reliance on that - certificate. (See: ABA Guidelines.) - - $ Remote Authentication Dial-In User Service (RADIUS) - (I) An Internet protocol [R2138] for carrying dial-in users' - authentication information and configuration information between a - - - -Shirey Informational [Page 141] - -RFC 2828 Internet Security Glossary May 2000 - - - shared, centralized authentication server (the RADIUS server) and - a network access server (the RADIUS client) that needs to - authenticate the users of its network access ports. (See: TACACS.) - - (C) A user of the RADIUS client presents authentication - information to the client, and the client passes that information - to the RADIUS server. The server authenticates the client using a - shared secret value, then checks the user's authentication - information, and finally returns to the client all authorization - and configuration information needed by the client to deliver - service to the user. - - $ renew - See: certificate renewal. - - $ replay attack - (I) An attack in which a valid data transmission is maliciously or - fraudulently repeated, either by the originator or by an adversary - who intercepts the data and retransmits it, possibly as part of a - masquerade attack. (See: active wiretapping.) - - $ repository - (I) A system for storing and distributing digital certificates and - related information (including CRLs, CPSs, and certificate - policies) to certificate users. (See: directory.) - - (O) "A trustworthy system for storing and retrieving certificates - or other information relevant to certificates." [ABA] - - (C) A certificate is published to those who might need it by - putting it in a repository. The repository usually is a publicly - accessible, on-line server. In the Federal Public-key - Infrastructure, for example, the expected repository is a - directory that uses LDAP, but also may be the X.500 Directory that - uses DAP, or an HTTP server, or an FTP server that permits - anonymous login. - - $ repudiation - (I) Denial by a system entity that was involved in an association - (especially an association that transfers information) of having - participated in the relationship. (See: accountability, non- - repudiation service.) - - (O) "Denial by one of the entities involved in a communication of - having participated in all or part of the communication." [I7498 - Part 2] - - - - - -Shirey Informational [Page 142] - -RFC 2828 Internet Security Glossary May 2000 - - - $ Request for Comment (RFC) - (I) One of the documents in the archival series that is the - official channel for ISDs and other publications of the Internet - Engineering Steering Group, the Internet Architecture Board, and - the Internet community in general. [R2026, R2223] (See: Internet - Standard.) - - (C) This term is *not* a synonym for "Internet Standard". - - $ residual risk - (I) The risk that remains after countermeasures have been applied. - - $ restore - See: card restore. - - $ revocation - See: certificate revocation. - - $ revocation date - (N) In an X.509 CRL entry, a date-time field that states when the - certificate revocation occurred, i.e., when the CA declared the - digital certificate to be invalid. (See: invalidity date.) - - (C) The revocation date may not resolve some disputes because, in - the worst case, all signatures made during the validity period of - the certificate may have to be considered invalid. However, it may - be desirable to treat a digital signature as valid even though the - private key used to sign was compromised after the signing. If - more is known about when the compromise actually occurred, a - second date-time, an "invalidity date", can be included in an - extension of the CRL entry. - - $ revocation list - See: certificate revocation list. - - $ revoke - See: certificate revocation. - - $ RFC - See: Request for Comment. - - $ risk - (I) An expectation of loss expressed as the probability that a - particular threat will exploit a particular vulnerability with a - particular harmful result. - - - - - - -Shirey Informational [Page 143] - -RFC 2828 Internet Security Glossary May 2000 - - - (O) SET usage: "The possibility of loss because of one or more - threats to information (not to be confused with financial or - business risk)." [SET2] - - $ risk analysis - $ risk assessment - (I) A process that systematically identifies valuable system - resources and threats to those resources, quantifies loss - exposures (i.e., loss potential) based on estimated frequencies - and costs of occurrence, and (optionally) recommends how to - allocate resources to countermeasures so as to minimize total - exposure. - - (C) The analysis lists risks in order of cost and criticality, - thereby determining where countermeasures should be applied first. - It is usually financially and technically infeasible to counteract - all aspects of risk, and so some residual risk will remain, even - after all available countermeasures have been deployed. [FP031, - R2196] - - $ risk management - (I) The process of identifying, controlling, and eliminating or - minimizing uncertain events that may affect system resources. - (See: risk analysis.) - - $ Rivest Cipher #2 (RC2) - (N) A proprietary, variable-key-length block cipher invented by - Ron Rivest for RSA Data Security, Inc. (now a wholly-owned - subsidiary of Security Dynamics, Inc.). - - $ Rivest Cipher #4 (RC4) - (N) A proprietary, variable-key-length stream cipher invented by - Ron Rivest for RSA Data Security, Inc. (now a wholly-owned - subsidiary of Security Dynamics, Inc.). - - $ Rivest-Shamir-Adleman (RSA) - (N) An algorithm for asymmetric cryptography, invented in 1977 by - Ron Rivest, Adi Shamir, and Leonard Adleman [RSA78, Schn]. - - (C) RSA uses exponentiation modulo the product of two large prime - numbers. The difficulty of breaking RSA is believed to be - equivalent to the difficulty of factoring integers that are the - product of two large prime numbers of approximately equal size. - - (C) To create an RSA key pair, randomly choose two large prime - numbers, p and q, and compute the modulus, n = pq. Randomly choose - a number e, the public exponent, that is less than n and - relatively prime to (p-1)(q-1). Choose another number d, the - - - -Shirey Informational [Page 144] - -RFC 2828 Internet Security Glossary May 2000 - - - private exponent, such that ed-1 evenly divides (p-1)(q-1). The - public key is the set of numbers (n,e), and the private key is the - set (n,d). - - (C) It is assumed to be difficult to compute the private key (n,d) - from the public key (n,e). However, if n can be factored into p - and q, then the private key d can be computed easily. Thus, RSA - security depends on the assumption that it is computationally - difficult to factor a number that is the product of two large - prime numbers. (Of course, p and q are treated as part of the - private key, or else destroyed after computing n.) - - (C) For encryption of a message, m, to be sent to Bob, Alice uses - Bob's public key (n,e) to compute m**e (mod n) = c. She sends c to - Bob. Bob computes c**d (mod n) = m. Only Bob knows d, so only Bob - can compute c**d (mod n) = m to recover m. - - (C) To provide data origin authentication of a message, m, to be - sent to Bob, Alice computes m**d (mod n) = s, where (d,n) is - Alice's private key. She sends m and s to Bob. To recover the - message that only Alice could have sent, Bob computes s**e (mod n) - = m, where (e,n) is Alice's public key. - - (C) To ensure data integrity in addition to data origin - authentication requires extra computation steps in which Alice and - Bob use a cryptographic hash function h (as explained for digital - signature). Alice computes the hash value h(m) = v, and then - encrypts v with her private key to get s. She sends m and s. Bob - receives m' and s', either of which might have been changed from - the m and s that Alice sent. To test this, he decrypts s' with - Alice's public key to get v'. He then computes h(m') = v". If v' - equals v", Bob is assured that m' is the same m that Alice sent. - - $ role-based access control (RBAC) - (I) A form of identity-based access control where the system - entities that are identified and controlled are functional - positions in an organization or process. - - $ root - (I) A CA that is directly trusted by an end entity. Acquiring the - value of a root CA's public key involves an out-of-band procedure. - - (I) Hierarchical PKI usage: The CA that is the highest level (most - trusted) CA in a certification hierarchy; i.e., the authority upon - whose public key all certificate users base their trust. (See: top - CA.) - - - - - -Shirey Informational [Page 145] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) In a hierarchical PKI, a root issues public-key certificates - to one or more additional CAs that form the second highest level. - Each of these CAs may issue certificates to more CAs at the third - highest level, and so on. To initialize operation of a - hierarchical PKI, the root's initial public key is securely - distributed to all certificate users in a way that does not depend - on the PKI's certification relationships. The root's public key - may be distributed simply as a numerical value, but typically is - distributed in a self-signed certificate in which the root is the - subject. The root's certificate is signed by the root itself - because there is no higher authority in a certification hierarchy. - The root's certificate is then the first certificate in every - certification path. - - (O) MISSI usage: A name previously used for a MISSI policy - creation authority, which is not a root as defined above for - general usage, but is a CA at the second level of the MISSI - hierarchy, immediately subordinate to a MISSI policy approving - authority. - - (O) UNIX usage: A user account (also called "superuser") that has - all privileges (including all security-related privileges) and - thus can manage the system and its other user accounts. - - $ root certificate - (I) A certificate for which the subject is a root. - - (I) Hierarchical PKI usage: The self-signed public-key certificate - at the top of a certification hierarchy. - - $ root key - (I) A public key for which the matching private key is held by a - root. - - $ root registry - (O) MISSI usage: A name previously used for a MISSI policy - approving authority. - - $ router - (I) A computer that is a gateway between two networks at OSI layer - 3 and that relays and directs data packets through that - internetwork. The most common form of router operates on IP - packets. (See: bridge.) - - (I) Internet usage: In the context of the Internet protocol suite, - a networked computer that forwards Internet Protocol packets that - are not addressed to the computer itself. (See: host.) - - - - -Shirey Informational [Page 146] - -RFC 2828 Internet Security Glossary May 2000 - - - $ RSA - See: Rivest-Shamir-Adleman. - - $ rule-based security policy - (I) "A security policy based on global rules imposed for all - users. These rules usually rely on comparison of the sensitivity - of the resource being accessed and the possession of corresponding - attributes of users, a group of users, or entities acting on - behalf of users." [I7498 Part 2] (See: identity-based security - policy.) - - $ safety - (I) The property of a system being free from risk of causing harm - to system entities and outside entities. - - $ SAID - See: security association identifier. - - $ salt - (I) A random value that is concatenated with a password before - applying the one-way encryption function used to protect passwords - that are stored in the database of an access control system. (See: - initialization value.) - - (C) Salt protects a password-based access control system against a - dictionary attack. - - $ sanitize - (I) Delete sensitive data from a file, a device, or a system; or - modify data so as to be able to downgrade its classification - level. - - $ SASL - See: Simple Authentication and Security Layer. - - $ SCA - See: subordinate certification authority. - - $ scavenging - See: (secondary definition under) threat consequence. - - $ screening router - (I) A synonym for "filtering router". - - $ SDE - See: Secure Data Exchange. - - - - - -Shirey Informational [Page 147] - -RFC 2828 Internet Security Glossary May 2000 - - - $ SDNS - See: Secure Data Network System. - - $ seal - (O) To use cryptography to provide data integrity service for a - data object. (See: sign, wrap.) - - (D) ISDs SHOULD NOT use this definition; instead, use language - that is more specific with regard to the mechanism(s) used, such - as "sign" when the mechanism is digital signature. - - $ secret - (I) (1.) Adjective: The condition of information being protected - from being known by any system entities except those who are - intended to know it. (2.) Noun: An item of information that is - protected thusly. - - (C) This term applies to symmetric keys, private keys, and - passwords. - - $ secret-key cryptography - (I) A synonym for "symmetric cryptography". - - $ Secure Data Exchange (SDE) - (N) A local area network security protocol defined by the IEEE - 802.10 standard. - - $ Secure Data Network System (SDNS) - (N) An NSA program that developed security protocols for - electronic mail (Message Security Protocol), OSI layer 3 (SP3), - OSI layer 4 (SP4), and key management (KMP). - - $ Secure Hash Standard (SHS) - (N) The U.S. Government standard [FP180] that specifies the Secure - Hash Algorithm (SHA-1), a cryptographic hash function that - produces a 160-bit output (hash result) for input data of any - length < 2**64 bits. - - $ Secure Hypertext Transfer Protocol (Secure-HTTP, S-HTTP) - (I) A Internet protocol for providing client-server security - services for HTTP communications. (See: https.) - - (C) S-HTTP was originally specified by CommerceNet, a coalition of - businesses interested in developing the Internet for commercial - uses. Several message formats may be incorporated into S-HTTP - clients and servers, particularly CMS and MOSS. S-HTTP supports - choice of security policies, key management mechanisms, and - cryptographic algorithms through option negotiation between - - - -Shirey Informational [Page 148] - -RFC 2828 Internet Security Glossary May 2000 - - - parties for each transaction. S-HTTP supports both asymmetric and - symmetric key operation modes. S-HTTP attempts to avoid presuming - a particular trust model, but it attempts to facilitate multiply- - rooted hierarchical trust and anticipates that principals may have - many public key certificates. - - $ Secure/MIME (S/MIME) - (I) Secure/Multipurpose Internet Mail Extensions, an Internet - protocol [R2633] to provide encryption and digital signatures for - Internet mail messages. - - $ Secure Sockets Layer (SSL) - (N) An Internet protocol (originally developed by Netscape - Communications, Inc.) that uses connection-oriented end-to-end - encryption to provide data confidentiality service and data - integrity service for traffic between a client (often a web - browser) and a server, and that can optionally provide peer entity - authentication between the client and the server. (See: Transport - Layer Security.) - - (C) SSL is layered below HTTP and above a reliable transport - protocol (TCP). SSL is independent of the application it - encapsulates, and any higher level protocol can layer on top of - SSL transparently. However, many Internet applications might be - better served by IPsec. - - (C) SSL has two layers: (a) SSL's lower layer, the SSL Record - Protocol, is layered on top of the transport protocol and - encapsulates higher level protocols. One such encapsulated - protocol is SSL Handshake Protocol. (b) SSL's upper layer provides - asymmetric cryptography for server authentication (verifying the - server's identity to the client) and optional client - authentication (verifying the client's identity to the server), - and also enables them to negotiate a symmetric encryption - algorithm and secret session key (to use for data confidentiality) - before the application protocol transmits or receives data. A - keyed hash provides data integrity service for encapsulated data. - - $ secure state - (I) A system condition in which no subject can access any object - in an unauthorized manner. (See: (secondary definition under) - Bell-LaPadula Model, clean system.) - - $ security - (I) (1.) Measures taken to protect a system. (2.) The condition of - a system that results from the establishment and maintenance of - - - - - -Shirey Informational [Page 149] - -RFC 2828 Internet Security Glossary May 2000 - - - measures to protect the system. (3.) The condition of system - resources being free from unauthorized access and from - unauthorized or accidental change, destruction, or loss. - - $ security architecture - (I) A plan and set of principles that describe (a) the security - services that a system is required to provide to meet the needs of - its users, (b) the system elements required to implement the - services, and (c) the performance levels required in the elements - to deal with the threat environment. (See: (discussion under) - security policy.) - - (C) A security architecture is the result of applying the system - engineering process. A complete system security architecture - includes administrative security, communication security, computer - security, emanations security, personnel security, and physical - security (e.g., see: [R2179]). A complete security architecture - needs to deal with both intentional, intelligent threats and - accidental kinds of threats. - - $ security association - (I) A relationship established between two or more entities to - enable them to protect data they exchange. The relationship is - used to negotiate characteristics of protection mechanisms, but - does not include the mechanisms themselves. (See: association.) - - (C) A security association describes how entities will use - security services. The relationship is represented by a set of - information that is shared between the entities and is agreed upon - and considered a contract between them. - - (O) IPsec usage: A simplex (uni-directional) logical connection - created for security purposes and implemented with either AH or - ESP (but not both). The security services offered by a security - association depend on the protocol selected, the IPsec mode - (transport or tunnel), the endpoints, and the election of optional - services within the protocol. A security association is identified - by a triple consisting of (a) a destination IP address, (b) a - protocol (AH or ESP) identifier, and (c) a Security Parameter - Index. - - $ security association identifier (SAID) - (I) A data field in a security protocol (such as NLSP or SDE), - used to identify the security association to which a protocol data - unit is bound. The SAID value is usually used to select a key for - decryption or authentication at the destination. (See: Security - Parameter Index.) - - - - -Shirey Informational [Page 150] - -RFC 2828 Internet Security Glossary May 2000 - - - $ security audit - (I) An independent review and examination of a system's records - and activities to determine the adequacy of system controls, - ensure compliance with established security policy and procedures, - detect breaches in security services, and recommend any changes - that are indicated for countermeasures. [I7498 Part 2, NCS01] - - (C) The basic audit objective is to establish accountability for - system entities that initiate or participate in security-relevant - events and actions. Thus, means are needed to generate and record - a security audit trail and to review and analyze the audit trail - to discover and investigate attacks and security compromises. - - $ security audit trail - (I) A chronological record of system activities that is sufficient - to enable the reconstruction and examination of the sequence of - environments and activities surrounding or leading to an - operation, procedure, or event in a security-relevant transaction - from inception to final results. [NCS04] (See: security audit.) - - $ security class - (D) A synonym for "security level". For consistency, ISDs SHOULD - use "security level" instead of "security class". - - $ security clearance - (I) A determination that a person is eligible, under the standards - of a specific security policy, for authorization to access - sensitive information or other system resources. (See: clearance - level.) - - $ security compromise - (I) A security violation in which a system resource is exposed, or - is potentially exposed, to unauthorized access. (See: data - compromise, violation.) - - $ security domain - See: domain. - - $ security environment - (I) The set of external entities, procedures, and conditions that - affect secure development, operation, and maintenance of a system. - - $ security event - (I) A occurrence in a system that is relevant to the security of - the system. (See: security incident.) - - - - - - -Shirey Informational [Page 151] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) The term includes both events that are security incidents and - those that are not. In a CA workstation, for example, a list of - security events might include the following: - - - Performing a cryptographic operation, e.g., signing a digital - certificate or CRL. - - Performing a cryptographic card operation: creation, insertion, - removal, or backup. - - Performing a digital certificate lifecycle operation: rekey, - renewal, revocation, or update. - - Posting information to an X.500 Directory. - - Receiving a key compromise notification. - - Receiving an improper certification request. - - Detecting an alarm condition reported by a cryptographic - module. - - Logging the operator in or out. - - Failing a built-in hardware self-test or a software system - integrity check. - - $ security fault analysis - (I) A security analysis, usually performed on hardware at a logic - gate level, gate-by-gate, to determine the security properties of - a device when a hardware fault is encountered. - - $ security gateway - (I) A gateway that separates trusted (or relatively more trusted) - hosts on the internal network side from untrusted (or less - trusted) hosts on the external network side. (See: firewall and - guard.) - - (O) IPsec usage: "An intermediate system that implements IPsec - protocols." [R2401] Normally, AH or ESP is implemented to serve a - set of internal hosts, providing security services for the hosts - when they communicate with other, external hosts or gateways that - also implement IPsec. - - $ security incident - (I) A security event that involves a security violation. (See: - CERT, GRIP, security event, security intrusion, security - violation.) - - (C) In other words, a security-relevant system event in which the - system's security policy is disobeyed or otherwise breached. - - (O) "Any adverse event which compromises some aspect of computer - or network security." [R2350] - - - - - -Shirey Informational [Page 152] - -RFC 2828 Internet Security Glossary May 2000 - - - (D) ISDs SHOULD NOT use this "O" definition because (a) a security - incident may occur without actually being harmful (i.e., adverse) - and (b) this Glossary defines "compromise" more narrowly in - relation to unauthorized access. - - $ security intrusion - (I) A security event, or a combination of multiple security - events, that constitutes a security incident in which an intruder - gains, or attempts to gain, access to a system (or system - resource) without having authorization to do so. - - $ security kernel - (I) "The hardware, firmware, and software elements of a trusted - computing base that implement the reference monitor concept. It - must mediate all accesses, be protected from modification, and be - verifiable as correct." [NCS04] (See: reference monitor.) - - (C) That is, a security kernel is an implementation of a reference - monitor for a given hardware base. - - $ security label - (I) A marking that is bound to a system resource and that names or - designates the security-relevant attributes of that resource. - [I7498 Part 2, R1457] - - (C) The recommended definition is usefully broad, but usually the - term is understood more narrowly as a marking that represents the - security level of an information object, i.e., a marking that - indicates how sensitive an information object is. [NCS04] - - (C) System security mechanisms interpret security labels according - to applicable security policy to determine how to control access - to the associated information, otherwise constrain its handling, - and affix appropriate security markings to visible (printed and - displayed) images thereof. [FP188] - - $ security level - (I) The combination of a hierarchical classification level and a - set of non-hierarchical category designations that represents how - sensitive information is. (See: (usage note under) classification - level, dominate, lattice model.) - - $ security management infrastructure (SMI) - (I) System elements and activities that support security policy by - monitoring and controlling security services and mechanisms, - distributing security information, and reporting security events. - The associated functions are as follows [I7498-4]: - - - - -Shirey Informational [Page 153] - -RFC 2828 Internet Security Glossary May 2000 - - - - Controlling (granting or restricting) access to system - resources: This includes verifying authorizations and - identities, controlling access to sensitive security data, and - modifying access priorities and procedures in the event of - attacks. - - - Retrieving (gathering) and archiving (storing) security - information: This includes logging security events and - analyzing the log, monitoring and profiling usage, and - reporting security violations. - - - Managing and controlling the encryption process: This includes - performing the functions of key management and reporting on key - management problems. (See: public-key infrastructure.) - - $ security mechanism - (I) A process (or a device incorporating such a process) that can - be used in a system to implement a security service that is - provided by or within the system. (See: (discussion under) - security policy.) - - (C) Some examples of security mechanisms are authentication - exchange, checksum, digital signature, encryption, and traffic - padding. - - $ security model - (I) A schematic description of a set of entities and relationships - by which a specified set of security services are provided by or - within a system. (See: (discussion under) security policy.) - - (C) An example is the Bell-LaPadula Model. - - $ security parameters index (SPI) - (I) IPsec usage: The type of security association identifier used - in IPsec protocols. A 32-bit value used to distinguish among - different security associations terminating at the same - destination (IP address) and using the same IPsec security - protocol (AH or ESP). Carried in AH and ESP to enable the - receiving system to determine under which security association to - process a received packet. - - $ security perimeter - (I) The boundary of the domain in which a security policy or - security architecture applies; i.e., the boundary of the space in - which security services protect system resources. - - - - - - -Shirey Informational [Page 154] - -RFC 2828 Internet Security Glossary May 2000 - - - $ security policy - (I) A set of rules and practices that specify or regulate how a - system or organization provides security services to protect - sensitive and critical system resources. (See: identity-based - security policy, rule-based security policy, security - architecture, security mechanism, security model.) - - (O) "The set of rules laid down by the security authority - governing the use and provision of security services and - facilities." [X509] - - (C) Ravi Sandhu notes that security policy is one of four layers - of the security engineering process (as shown in the following - diagram). Each layer provides a different view of security, - ranging from what services are needed to how services are - implemented. - - What Security Services Should Be Provided? - ^ - | + - - - - - - - - - - - + - | | Security Policy | - | + - - - - - - - - - - - + + - - - - - - - - - - - - - - + - | | Security Model | | A "top-level specification" | - | + - - - - - - - - - - - + <- | is at a level below "model" | - | | Security Architecture | | but above "architecture". | - | + - - - - - - - - - - - + + - - - - - - - - - - - - - - + - | | Security Mechanism | - | + - - - - - - - - - - - + - v - How Are Security Services Implemented? - - $ Security Protocol 3 (SP3) - (O) A protocol [SDNS3] developed by SDNS to provide connectionless - data security at the top of OSI layer 3. (See: NLSP.) - - $ Security Protocol 4 (SP4) - (O) A protocol [SDNS4] developed by SDNS to provide either - connectionless or end-to-end connection-oriented data security at - the bottom of OSI layer 4. (See: TLSP.) - - $ security-relevant event - See: security event. - - $ security service - (I) A processing or communication service that is provided by a - system to give a specific kind of protection to system resources. - (See: access control service, audit service, availability service, - - - - -Shirey Informational [Page 155] - -RFC 2828 Internet Security Glossary May 2000 - - - data confidentiality service, data integrity service, data origin - authentication service, non-repudiation service, peer entity - authentication service, system integrity service.) - - (O) "A service, provided by a layer of communicating open systems, - which ensures adequate security of the systems or the data - transfers." [I7498 Part 2] - - (C) Security services implement security policies, and are - implemented by security mechanisms. - - $ security situation - (I) ISAKMP usage: The set of all security-relevant information-- - e.g., network addresses, security classifications, manner of - operation (normal or emergency)--that is needed to decide the - security services that are required to protect the association - that is being negotiated. - - $ security token - See: token. - - $ security violation - (I) An act or event that disobeys or otherwise breaches security - policy. (See: compromise, penetration, security incident.) - - $ self-signed certificate - (I) A public-key certificate for which the public key bound by the - certificate and the private key used to sign the certificate are - components of the same key pair, which belongs to the signer. - (See: root certificate.) - - (C) In a self-signed X.509 public-key certificate, the issuer's DN - is the same as the subject's DN. - - $ semantic security - (I) An attribute of a encryption algorithm that is a formalization - of the notion that the algorithm not only hides the plaintext but - also reveals no partial information about the plaintext. Whatever - is efficiently computable about the plaintext when given the - ciphertext, is also efficiently computable without the ciphertext. - (See: indistinguishability.) - - $ sensitive (information) - (I) Information is sensitive if disclosure, alteration, - destruction, or loss of the information would adversely affect the - interests or business of its owner or user. (See: critical.) - - - - - -Shirey Informational [Page 156] - -RFC 2828 Internet Security Glossary May 2000 - - - $ separation of duties - (I) The practice of dividing the steps in a system function among - different individuals, so as to keep a single individual from - subverting the process. (See: dual control, administrative - security.) - - $ serial number - See: certificate serial number. - - $ server - (I) A system entity that provides a service in response to - requests from other system entities called clients. - - $ session key - (I) In the context of symmetric encryption, a key that is - temporary or is used for a relatively short period of time. (See: - ephemeral key, key distribution center, master key.) - - (C) Usually, a session key is used for a defined period of - communication between two computers, such as for the duration of a - single connection or transaction set, or the key is used in an - application that protects relatively large amounts of data and, - therefore, needs to be rekeyed frequently. - - $ SET - See: SET Secure Electronic Transaction(trademark). - - $ SET private extension - (O) One of the private extensions defined by SET for X.509 - certificates. Carries information about hashed root key, - certificate type, merchant data, cardholder certificate - requirements, encryption support for tunneling, or message support - for payment instructions. - - $ SET qualifier - (O) A certificate policy qualifier that provides information about - the location and content of a SET certificate policy. - - (C) In addition to the policies and qualifiers inherited from its - own certificate, each CA in the SET certification hierarchy may - add one qualifying statement to the root policy when the CA issues - a certificate. The additional qualifier is a certificate policy - for that CA. Each policy in a SET certificate may have these - qualifiers: - - - A URL where a copy of the policy statement may be found. - - An electronic mail address where a copy of the policy statement - may be found. - - - -Shirey Informational [Page 157] - -RFC 2828 Internet Security Glossary May 2000 - - - - A hash result of the policy statement, computed using the - indicated algorithm. - - A statement declaring any disclaimers associated with the - issuing of the certificate. - - $ SET Secure Electronic Transaction(trademark) or SET(trademark) - (N) A protocol developed jointly by MasterCard International and - Visa International and published as an open standard to provide - confidentiality of transaction information, payment integrity, and - authentication of transaction participants for payment card - transactions over unsecured networks, such as the Internet. [SET1] - (See: acquirer, brand, cardholder, dual signature, electronic - commerce, issuer, merchant, payment gateway, third party.) - - (C) This term and acronym are trademarks of SETCo. MasterCard and - Visa announced the SET standard on 1 February 1996. On 19 December - 1997, MasterCard and Visa formed SET Secure Electronic Transaction - LLC (commonly referred to as "SETCo") to implement the SET 1.0 - specification. A memorandum of understanding adds American Express - and JCB Credit Card Company as co-owners of SETCo. - - $ SETCo - See: (secondary definition under) SET Secure Electronic - Transaction. - - $ SHA-1 - See: Secure Hash Standard. - - $ shared secret - (I) A synonym for "keying material" or "cryptographic key". - - $ S-HTTP - See: Secure HTTP. - - $ sign - (I) Create a digital signature for a data object. - - $ signature - See: digital signature, electronic signature. - - $ signature certificate - (I) A public-key certificate that contains a public key that is - intended to be used for verifying digital signatures, rather than - for encrypting data or performing other cryptographic functions. - - (C) A v3 X.509 public-key certificate may have a "keyUsage" - extension which indicates the purpose for which the certified - public key is intended. - - - -Shirey Informational [Page 158] - -RFC 2828 Internet Security Glossary May 2000 - - - $ signer - (N) A human being or an organization entity that uses its private - key to create a digital signature for a data object. [ABA] - - $ SILS - See: Standards for Interoperable LAN/MAN Security. - - $ simple authentication - (I) An authentication process that uses a password as the - information needed to verify an identity claimed for an entity. - (See: strong authentication.) - - (O) "Authentication by means of simple password arrangements." - [X509] - - $ Simple Authentication and Security Layer (SASL) - (I) An Internet specification [R2222] for adding authentication - service to connection-based protocols. To use SASL, a protocol - includes a command for authenticating a user to a server and for - optionally negotiating protection of subsequent protocol - interactions. The command names a registered security mechanism. - SASL mechanisms include Kerberos, GSSAPI, S/KEY, and others. Some - protocols that use SASL are IMAP4 and POP3. - - $ Simple Key-management for Internet Protocols (SKIP) - (I) A key distribution protocol that uses hybrid encryption to - convey session keys that are used to encrypt data in IP packets. - [R2356] (See: IKE, IPsec.) - - (C) SKIP uses the Diffie-Hellman algorithm (or could use another - key agreement algorithm) to generate a key-encrypting key for use - between two entities. A session key is used with a symmetric - algorithm to encrypt data in one or more IP packets that are to be - sent from one of the entities to the other. The KEK is used with a - symmetric algorithm to encrypt the session key, and the encrypted - session key is placed in a SKIP header that is added to each IP - packet that is encrypted with that session key. - - $ Simple Mail Transfer Protocol (SMTP) - (I) A TCP-based, application-layer, Internet Standard protocol - [R0821] for moving electronic mail messages from one computer to - another. - - $ Simple Network Management Protocol (SNMP) - (I) A UDP-based, application-layer, Internet Standard protocol - [R2570, R2574] for conveying management information between - managers and agents. - - - - -Shirey Informational [Page 159] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) SNMP version 1 uses cleartext passwords for authentication and - access control. (See: community string.) Version 2 adds - cryptographic mechanisms based on DES and MD5. Version 3 provides - enhanced, integrated support for security services, including data - confidentiality, data integrity, data origin authentication, and - message timeliness and limited replay protection. - - $ simple security property - See: (secondary definition under) Bell-LaPadula Model. - - $ single sign-on - (I) A system that enables a user to access multiple computer - platforms (usually a set of hosts on the same network) or - application systems after being authenticated just one time. (See: - Kerberos.) - - (C) Typically, a user logs in just once, and then is transparently - granted access to a variety of permitted resources with no further - login being required until after the user logs out. Such a system - has the advantages of being user friendly and enabling - authentication to be managed consistently across an entire - enterprise, and has the disadvantage of requiring all hosts and - applications to trust the same authentication mechanism. - - $ situation - See: security situation. - - $ S/Key - (I) A security mechanism that uses a cryptographic hash function - to generate a sequence of 64-bit, one-time passwords for remote - user login. [R1760] - - (C) The client generates a one-time password by applying the MD4 - cryptographic hash function multiple times to the user's secret - key. For each successive authentication of the user, the number of - hash applications is reduced by one. (Thus, an intruder using - wiretapping cannot compute a valid password from knowledge of one - previously used.) The server verifies a password by hashing the - currently presented password (or initialization value) one time - and comparing the hash result with the previously presented - password. - - $ SKIP - See: Simple Key-management for IP. - - - - - - - -Shirey Informational [Page 160] - -RFC 2828 Internet Security Glossary May 2000 - - - $ SKIPJACK - (N) A Type II block cipher [NIST] with a block size of 64 bits and - a key size of 80 bits, that was developed by NSA and formerly - classified at the U.S. Department of Defense "Secret" level. (See: - CAPSTONE, CLIPPER, FORTEZZA, Key Exchange Algorithm.) - - (C) On 23 June 1998, NSA announced that SKIPJACK had been - declassified. - - $ slot - (O) MISSI usage: One of the FORTEZZA PC card storage areas that - are each able to hold an X.509 certificate and additional data - that is associated with the certificate, such as the matching - private key. - - $ smart card - (I) A credit-card sized device containing one or more integrated - circuit chips, which perform the functions of a computer's central - processor, memory, and input/output interface. (See: PC card.) - - (C) Sometimes this term is used rather strictly to mean a card - that closely conforms to the dimensions and appearance of the kind - of plastic credit card issued by banks and merchants. At other - times, the term is used loosely to include cards that are larger - than credit cards, especially cards that are thicker, such as PC - cards. - - (C) A "smart token" is a device that conforms to the definition of - smart card except that rather than having standard credit card - dimensions, the token is packaged in some other form, such as a - dog tag or door key shape. - - $ smart token - See: (secondary definition under) smart card. - - $ SMI - See: security management infrastructure. - - $ S/MIME - See: Secure/MIME. - - $ SMTP - See: Simple Mail Transfer Protocol. - - $ smurf - (I) Software that mounts a denial-of-service attack ("smurfing") - by exploiting IP broadcast addressing and ICMP ping packets to - cause flooding. (See: flood, ICMP flood.) - - - -Shirey Informational [Page 161] - -RFC 2828 Internet Security Glossary May 2000 - - - (D) ISDs SHOULD NOT use this term because it is not listed in most - dictionaries and could confuse international readers. - - (C) A smurf program builds a network packet that appears to - originate from another address, that of the "victim", either a - host or an IP router. The packet contains an ICMP ping message - that is addressed to an IP broadcast address, i.e., to all IP - addresses in a given network. The echo responses to the ping - message return to the victim's address. The goal of smurfing may - be either to deny service at a particular host or to flood all or - part of an IP network. - - $ sniffing - (C) A synonym for "passive wiretapping". (See: password sniffing.) - - (D) ISDs SHOULD NOT use this term because it unnecessarily - duplicates the meaning of a term that is better established. (See: - (usage note under) Green Book. - - $ SNMP - See: Simple Network Management Protocol. - - $ social engineering - (I) A euphemism for non-technical or low-technology means--such as - lies, impersonation, tricks, bribes, blackmail, and threats--used - to attack information systems. (See: masquerade attack.) - - (D) ISDs SHOULD NOT use this term because it is vague; instead, - use a term that is specific with regard to the means of attack. - - $ SOCKS - (I) An Internet protocol [R1928] that provides a generalized proxy - server that enables client-server applications--such as TELNET, - FTP, and HTTP; running over either TCP or UDP--to use the services - of a firewall. - - (C) SOCKS is layered under the application layer and above the - transport layer. When a client inside a firewall wishes to - establish a connection to an object that is reachable only through - the firewall, it uses TCP to connect to the SOCKS server, - negotiates with the server for the authentication method to be - used, authenticates with the chosen method, and then sends a relay - request. The SOCKS server evaluates the request, typically based - on source and destination addresses, and either establishes the - appropriate connection or denies it. - - - - - - -Shirey Informational [Page 162] - -RFC 2828 Internet Security Glossary May 2000 - - - $ soft TEMPEST - (O) The use of software techniques to reduce the radio frequency - information leakage from computer displays and keyboards. [Kuhn] - (See: TEMPEST.) - - $ software - (I) Computer programs (which are stored in and executed by - computer hardware) and associated data (which also is stored in - the hardware) that may be dynamically written or modified during - execution. (See: firmware, hardware.) - - $ SORA - See: SSO-PIN ORA. - - $ source authentication - (D) ISDs SHOULD NOT use this term because it is ambiguous. If the - intent is to authenticate the original creator or packager of data - received, then say "data origin authentication". If the intent is - to authenticate the identity of the sender of data, then say "peer - entity authentication". (See: data origin authentication, peer - entity authentication). - - $ source integrity - (I) The degree of confidence that can be placed in information - based on the trustworthiness of its sources. (See: integrity.) - - $ SP3 - See: Security Protocol 3. - - $ SP4 - See: Security Protocol 4. - - $ spam - (I) (1.) Verb: To indiscriminately send unsolicited, unwanted, - irrelevant, or inappropriate messages, especially commercial - advertising in mass quantities. (2.) Noun: electronic "junk mail". - [R2635] - - (D) This term SHOULD NOT be written in upper-case letters, because - SPAM(trademark) is a trademark of Hormel Foods Corporation. Hormel - says, "We do not object to use of this slang term [spam] to - describe [unsolicited commercial email (UCE)], although we do - object to the use of our product image in association with that - term. Also, if the term is to be used, it should be used in all - lower-case letters to distinguish it from our trademark SPAM, - which should be used with all uppercase letters." - - - - - -Shirey Informational [Page 163] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) In sufficient volume, spam can cause denial of service. (See: - flooding.) According to the SPAM Web site, the term was adopted as - a result of the Monty Python skit in which a group of Vikings sang - a chorus of 'SPAM, SPAM, SPAM . . .' in an increasing crescendo, - drowning out other conversation. Hence, the analogy applied - because UCE was drowning out normal discourse on the Internet. - - $ SPC - See: software publisher certificate. - - $ SPI - See: Security Parameters Index. - - $ split key - (I) A cryptographic key that is divided into two or more separate - data items that individually convey no knowledge of the whole key - that results from combining the items. (See: dual control, split - knowledge.) - - $ split knowledge - (I) A security technique in which two or more entities separately - hold data items that individually convey no knowledge of the - information that results from combining the items. (See: dual - control, split key.) - - (O) "A condition under which two or more entities separately have - key components which individually convey no knowledge of the - plaintext key which will be produced when the key components are - combined in the cryptographic module." [FP140] - - $ spoofing attack - (I) A synonym for "masquerade attack". - - $ SSH - (I) A protocol for secure remote login and other secure network - services over an insecure network. - - (C) Consists of three major components: - - - Transport layer protocol: Provides server authentication, - confidentiality, and integrity. It may optionally also provide - compression. The transport layer will typically be run over a - TCP/IP connection, but might also be used on top of any other - reliable data stream. - - - User authentication protocol: Authenticates the client-side - user to the server. It runs over the transport layer protocol. - - - - -Shirey Informational [Page 164] - -RFC 2828 Internet Security Glossary May 2000 - - - - Connection protocol: Multiplexes the encrypted tunnel into - several logical channels. It runs over the user authentication - protocol. - - $ SSL - See: Secure Sockets Layer, Standard Security Label. - - $ SSO - See: system security officer. - - $ SSO PIN - (O) MISSI usage: One of two personal identification numbers that - control access to the functions and stored data of a FORTEZZA PC - card. Knowledge of the SSO PIN enables the card user to perform - the FORTEZZA functions intended for use by an end user and also - the functions intended for use by a MISSI certification authority. - (See: user PIN.) - - $ SSO-PIN ORA (SORA) - (O) MISSI usage: A MISSI organizational RA that operates in a mode - in which the ORA performs all card management functions and, - therefore, requires knowledge of the SSO PIN for an end user's - FORTEZZA PC card. - - $ Standards for Interoperable LAN/MAN Security (SILS) - (N) (1.) The IEEE 802.10 standards committee. (2.) A developing - set of IEEE standards, which has eight parts: (a) Model, including - security management, (b) Secure Data Exchange protocol, (c) Key - Management, (d) [has been incorporated in (a)], (e) SDE Over - Ethernet 2.0, (f) SDE Sublayer Management, (g) SDE Security - Labels, and (h) SDE PICS Conformance. Parts b, e, f, g, and h are - incorporated in IEEE Standard 802.10-1998. - - $ star property - (I) (Written "*-property".) See: "confinement property" under - Bell-LaPadula Model. - - $ Star Trek attack - (C) An attack that penetrates your system where no attack has ever - gone before. - - $ steganography - (I) Methods of hiding the existence of a message or other data. - This is different than cryptography, which hides the meaning of a - message but does not hide the message itself. (See: cryptology.) - - (C) An example of a steganographic method is "invisible" ink. - (See: digital watermark.) - - - -Shirey Informational [Page 165] - -RFC 2828 Internet Security Glossary May 2000 - - - $ storage channel - See: (secondary definition under) covert channel. - - $ stream cipher - (I) An encryption algorithm that breaks plaintext into a stream of - successive bits (or characters) and encrypts the n-th plaintext - bit with the n-th element of a parallel key stream, thus - converting the plaintext bit stream into a ciphertext bit stream. - [Schn] (See: block cipher.) - - $ strong authentication - (I) An authentication process that uses cryptography--particularly - public-key certificates--to verify the identity claimed for an - entity. (See: X.509.) - - (O) "Authentication by means of cryptographically derived - credentials." [X509] - - $ subject - 1. (I) In a computer system: A system entity that causes - information to flow among objects or changes the system state; - technically, a process-domain pair. (See: Bell-LaPadula Model.) - - 2. (I) Of a certificate: The entity name that is bound to the data - items in a digital certificate, and particularly a name that is - bound to a key value in a public-key certificate. - - $ subnetwork - (N) An OSI term for a system of packet relays and connecting links - that implement the lower three protocol layers of the OSIRM to - provide a communication service that interconnects attached end - systems. Usually the relays operate at OSI layer 3 and are all of - the same type (e.g., all X.25 packet switches, or all interface - units in an IEEE 802.3 LAN). (See: gateway, internet, router.) - - $ subordinate certification authority (SCA) - (I) A CA whose public-key certificate is issued by another - (superior) CA. (See: certification hierarchy.) - - (O) MISSI usage: The fourth-highest (bottom) level of a MISSI - certification hierarchy; a MISSI CA whose public-key certificate - is signed by a MISSI CA rather than by a MISSI PCA. A MISSI SCA is - the administrative authority for a subunit of an organization, - established when it is desirable to organizationally distribute or - decentralize the CA service. The term refers both to that - authoritative office or role, and to the person who fills that - - - - - -Shirey Informational [Page 166] - -RFC 2828 Internet Security Glossary May 2000 - - - office. A MISSI SCA registers end users and issues their - certificates and may also register ORAs, but may not register - other CAs. An SCA periodically issues a CRL. - - $ subordinate distinguished name - (I) An X.500 DN is subordinate to another X.500 DN if it begins - with a set of attributes that is the same as the entire second DN - except for the terminal attribute of the second DN (which is - usually the name of a CA). For example, the DN is subordinate to the DN - . - - $ superencryption - (I) An encryption operation for which the plaintext input to be - transformed is the ciphertext output of a previous encryption - operation. - - $ survivability - (I) The ability of a system to remain in operation or existence - despite adverse conditions, including both natural occurrences, - accidental actions, and attacks on the system. (See: availability, - reliability.) - - $ symmetric cryptography - (I) A branch of cryptography involving algorithms that use the - same key for two different steps of the algorithm (such as - encryption and decryption, or signature creation and signature - verification). (See: asymmetric cryptography.) - - (C) Symmetric cryptography has been used for thousands of years - [Kahn]. A modern example of a symmetric encryption algorithm is - the U.S. Government's Data Encryption Algorithm. (See: DEA, DES.) - - (C) Symmetric cryptography is sometimes called "secret-key - cryptography" (versus public-key cryptography) because the - entities that share the key, such as the originator and the - recipient of a message, need to keep the key secret. For example, - when Alice wants to ensure confidentiality for data she sends to - Bob, she encrypts the data with a secret key, and Bob uses the - same key to decrypt. Keeping the shared key secret entails both - cost and risk when the key is distributed to both Alice and Bob. - Thus, symmetric cryptography has a key management disadvantage - compared to asymmetric cryptography. - - $ symmetric key - (I) A cryptographic key that is used in a symmetric cryptographic - algorithm. - - - - -Shirey Informational [Page 167] - -RFC 2828 Internet Security Glossary May 2000 - - - $ SYN flood - (I) A denial of service attack that sends a host more TCP SYN - packets (request to synchronize sequence numbers, used when - opening a connection) than the protocol implementation can handle. - (See: flooding.) - - $ system - (C) In this Glossary, the term is mainly used as an abbreviation - for "automated information system". - - $ system entity - (I) An active element of a system--e.g., an automated process, a - subsystem, a person or group of persons--that incorporates a - specific set of capabilities. - - $ system high - (I) The highest security level supported by a system at a - particular time or in a particular environment. (See: system high - security mode.) - - $ system high security mode - (I) A mode of operation of an information system, wherein all - users having access to the system possess a security clearance or - authorization, but not necessarily a need-to-know, for all data - handled by the system. (See: mode of operation.) - - (C) This mode is defined formally in U.S. Department of Defense - policy regarding system accreditation [DOD2], but the term is - widely used outside the Defense Department and outside the - Government. - - $ system integrity - (I) "The quality that a system has when it can perform its - intended function in a unimpaired manner, free from deliberate or - inadvertent unauthorized manipulation." [NCS04] (See: system - integrity service.) - - $ system integrity service - (I) A security service that protects system resources in a - verifiable manner against unauthorized or accidental change, loss, - or destruction. (See: system integrity.) - - $ system low - (I) The lowest security level supported by a system at a - particular time or in a particular environment. (See: system - high.) - - - - - -Shirey Informational [Page 168] - -RFC 2828 Internet Security Glossary May 2000 - - - $ system resource - (I) Data contained in an information system; or a service provided - by a system; or a system capability, such as processing power or - communication bandwidth; or an item of system equipment (i.e., a - system component--hardware, firmware, software, or documentation); - or a facility that houses system operations and equipment. - - $ system security officer (SSO) - (I) A person responsible for enforcement or administration of the - security policy that applies to the system. - - $ system verification - See: (secondary definition under) verification. - - $ TACACS - $ TACACS+ - See: Terminal Access Controller (TAC) Access Control System. - - $ tamper - (I) Make an unauthorized modification in a system that alters the - system's functioning in a way that degrades the security services - that the system was intended to provide. - - $ TCB - See: trusted computing base. - - $ TCP - See: Transmission Control Protocol. - - $ TCP/IP - (I) A synonym for "Internet Protocol Suite", in which the - Transmission Control Protocol (TCP) and the Internet Protocol (IP) - are important parts. - - $ TCSEC - See: Trusted Computer System Evaluation Criteria. - - $ TELNET - (I) A TCP-based, application-layer, Internet Standard protocol - [R0854] for remote login from one host to another. - - $ TEMPEST - (O) A nickname for specifications and standards for limiting the - strength of electromagnetic emanations from electrical and - electronic equipment and thus reducing vulnerability to - eavesdropping. This term originated in the U.S. Department of - Defense. [Army, Kuhn, Russ] (See: emanation security, soft - tempest.) - - - -Shirey Informational [Page 169] - -RFC 2828 Internet Security Glossary May 2000 - - - (D) ISDs SHOULD NOT use this term as a synonym for - "electromagnetic emanations security". - - $ Terminal Access Controller (TAC) Access Control System (TACACS) - (I) A UDP-based authentication and access control protocol [R1492] - in which a network access server receives an identifier and - password from a remote terminal and passes them to a separate - authentication server for verification. - - (C) TACACS was developed for ARPANET and has evolved for use in - commercial equipment. TACs were a type of network access server - computer used to connect terminals to the early Internet, usually - using dial-up modem connections. TACACS used centralized - authentication servers and served not only network access servers - like TACs but also routers and other networked computing devices. - TACs are no longer in use, but TACACS+ is. [R1983] - - - "XTACACS": The name of Cisco Corporation's implementation, - which enhances and extends the original TACACS. - - - "TACACS+": A TCP-based protocol that improves on TACACS and - XTACACS by separating the functions of authentication, - authorization, and accounting and by encrypting all traffic - between the network access server and authentication server. It - is extensible to allow any authentication mechanism to be used - with TACACS+ clients. - - $ TESS - See: The Exponential Encryption System. - - $ The Exponential Encryption System (TESS) - (I) A system of separate but cooperating cryptographic mechanisms - and functions for the secure authenticated exchange of - cryptographic keys, the generation of digital signatures, and the - distribution of public keys. TESS employs asymmetric cryptography, - based on discrete exponentiation, and a structure of self- - certified public keys. [R1824] - - $ threat - (I) A potential for violation of security, which exists when there - is a circumstance, capability, action, or event that could breach - security and cause harm. (See: attack, threat action, threat - consequence.) - - (C) That is, a threat is a possible danger that might exploit a - vulnerability. A threat can be either "intentional" (i.e., - intelligent; e.g., an individual cracker or a criminal - - - - -Shirey Informational [Page 170] - -RFC 2828 Internet Security Glossary May 2000 - - - organization) or "accidental" (e.g., the possibility of a computer - malfunctioning, or the possibility of an "act of God" such as an - earthquake, a fire, or a tornado). - - (C) In some contexts, such as the following, the term is used - narrowly to refer only to intelligent threats: - - (N) U. S. Government usage: The technical and operational - capability of a hostile entity to detect, exploit, or subvert - friendly information systems and the demonstrated, presumed, or - inferred intent of that entity to conduct such activity. - - $ threat action - (I) An assault on system security. (See: attack, threat, threat - consequence.) - - (C) A complete security architecture deals with both intentional - acts (i.e. attacks) and accidental events [FIPS31]. Various kinds - of threat actions are defined as subentries under "threat - consequence". - - $ threat analysis - (I) An analysis of the probability of occurrences and consequences - of damaging actions to a system. - - $ threat consequence - (I) A security violation that results from a threat action. - Includes disclosure, deception, disruption, and usurpation. (See: - attack, threat, threat action.) - - (C) The following subentries describe four kinds of threat - consequences, and also list and describe the kinds of threat - actions that cause each consequence. Threat actions that are - accidental events are marked by "*". - - 1. "(Unauthorized) Disclosure" (a threat consequence): A - circumstance or event whereby an entity gains access to data - for which the entity is not authorized. (See: data - confidentiality.) The following threat actions can cause - unauthorized disclosure: - - A. "Exposure": A threat action whereby sensitive data is - directly released to an unauthorized entity. This includes: - - a. "Deliberate Exposure": Intentional release of sensitive - data to an unauthorized entity. - - - - - -Shirey Informational [Page 171] - -RFC 2828 Internet Security Glossary May 2000 - - - b. "Scavenging": Searching through data residue in a system - to gain unauthorized knowledge of sensitive data. - - c* "Human error": Human action or inaction that - unintentionally results in an entity gaining unauthorized - knowledge of sensitive data. - - d* "Hardware/software error". System failure that results in - an entity gaining unauthorized knowledge of sensitive - data. - - B. "Interception": A threat action whereby an unauthorized - entity directly accesses sensitive data traveling between - authorized sources and destinations. This includes: - - a. "Theft": Gaining access to sensitive data by stealing a - shipment of a physical medium, such as a magnetic tape or - disk, that holds the data. - - b. "Wiretapping (passive)": Monitoring and recording data - that is flowing between two points in a communication - system. (See: wiretapping.) - - c. "Emanations analysis": Gaining direct knowledge of - communicated data by monitoring and resolving a signal - that is emitted by a system and that contains the data - but is not intended to communicate the data. (See: - emanation.) - - C. "Inference": A threat action whereby an unauthorized entity - indirectly accesses sensitive data (but not necessarily the - data contained in the communication) by reasoning from - characteristics or byproducts of communications. This - includes: - - a. Traffic analysis: Gaining knowledge of data by observing - the characteristics of communications that carry the - data. (See: (main Glossary entry for) traffic analysis.) - - b. "Signals analysis": Gaining indirect knowledge of - communicated data by monitoring and analyzing a signal - that is emitted by a system and that contains the data - but is not intended to communicate the data. (See: - emanation.) - - D. "Intrusion": A threat action whereby an unauthorized entity - gains access to sensitive data by circumventing a system's - security protections. This includes: - - - -Shirey Informational [Page 172] - -RFC 2828 Internet Security Glossary May 2000 - - - a. "Trespass": Gaining unauthorized physical access to - sensitive data by circumventing a system's protections. - - b. "Penetration": Gaining unauthorized logical access to - sensitive data by circumventing a system's protections. - - c. "Reverse engineering": Acquiring sensitive data by - disassembling and analyzing the design of a system - component. - - d. Cryptanalysis: Transforming encrypted data into plaintext - without having prior knowledge of encryption parameters - or processes. (See: (main Glossary entry for) - cryptanalysis.) - - 2. "Deception" (a threat consequence): A circumstance or event - that may result in an authorized entity receiving false data - and believing it to be true. The following threat actions can - cause deception: - - A. "Masquerade": A threat action whereby an unauthorized entity - gains access to a system or performs a malicious act by - posing as an authorized entity. (See: (main Glossary entry - for) masquerade attack.) - - a. "Spoof": Attempt by an unauthorized entity to gain access - to a system by posing as an authorized user. - - b. "Malicious logic": In context of masquerade, any - hardware, firmware, or software (e.g., Trojan horse) that - appears to perform a useful or desirable function, but - actually gains unauthorized access to system resources or - tricks a user into executing other malicious logic. (See: - (main Glossary entry for) malicious logic.) - - B. "Falsification": A threat action whereby false data deceives - an authorized entity. (See: active wiretapping.) - - a. "Substitution": Altering or replacing valid data with - false data that serves to deceive an authorized entity. - - b. "Insertion": Introducing false data that serves to - deceive an authorized entity. - - C. "Repudiation": A threat action whereby an entity deceives - another by falsely denying responsibility for an act. (See: - non-repudiation service, (main Glossary entry for) - repudiation.) - - - -Shirey Informational [Page 173] - -RFC 2828 Internet Security Glossary May 2000 - - - a. "False denial of origin": Action whereby the originator - of data denies responsibility for its generation. - - b. "False denial of receipt": Action whereby the recipient - of data denies receiving and possessing the data. - - 3. "Disruption" (a threat consequence): A circumstance or event - that interrupts or prevents the correct operation of system - services and functions. (See: denial of service.) The following - threat actions can cause disruption: - - A. "Incapacitation": A threat action that prevents or - interrupts system operation by disabling a system component. - - a. "Malicious logic": In context of incapacitation, any - hardware, firmware, or software (e.g., logic bomb) - intentionally introduced into a system to destroy system - functions or resources. (See: (main Glossary entry for) - malicious logic.) - - b. "Physical destruction": Deliberate destruction of a - system component to interrupt or prevent system - operation. - - c* "Human error": Action or inaction that unintentionally - disables a system component. - - d* "Hardware or software error": Error that causes failure - of a system component and leads to disruption of system - operation. - - e* "Natural disaster": Any "act of God" (e.g., fire, flood, - earthquake, lightning, or wind) that disables a system - component. [FP031 section 2] - - B. "Corruption": A threat action that undesirably alters system - operation by adversely modifying system functions or data. - - a. "Tamper": In context of corruption, deliberate alteration - of a system's logic, data, or control information to - interrupt or prevent correct operation of system - functions. - - b. "Malicious logic": In context of corruption, any - hardware, firmware, or software (e.g., a computer virus) - intentionally introduced into a system to modify system - functions or data. (See: (main Glossary entry for) - malicious logic.) - - - -Shirey Informational [Page 174] - -RFC 2828 Internet Security Glossary May 2000 - - - c* "Human error": Human action or inaction that - unintentionally results in the alteration of system - functions or data. - - d* "Hardware or software error": Error that results in the - alteration of system functions or data. - - e* "Natural disaster": Any "act of God" (e.g., power surge - caused by lightning) that alters system functions or - data. [FP031 section 2] - - C. "Obstruction": A threat action that interrupts delivery of - system services by hindering system operations. - - a. "Interference": Disruption of system operations by - blocking communications or user data or control - information. - - b. "Overload": Hindrance of system operation by placing - excess burden on the performance capabilities of a system - component. (See: flooding.) - - 4. "Usurpation" (a threat consequence): A circumstance or event - that results in control of system services or functions by an - unauthorized entity. The following threat actions can cause - usurpation: - - A. "Misappropriation": A threat action whereby an entity - assumes unauthorized logical or physical control of a system - resource. - - a. "Theft of service": Unauthorized use of service by an - entity. - - b. "Theft of functionality": Unauthorized acquisition of - actual hardware, software, or firmware of a system - component. - - c. "Theft of data": Unauthorized acquisition and use of - data. - - B. "Misuse": A threat action that causes a system component to - perform a function or service that is detrimental to system - security. - - a. "Tamper": In context of misuse, deliberate alteration of - a system's logic, data, or control information to cause - the system to perform unauthorized functions or services. - - - -Shirey Informational [Page 175] - -RFC 2828 Internet Security Glossary May 2000 - - - b. "Malicious logic": In context of misuse, any hardware, - software, or firmware intentionally introduced into a - system to perform or control execution of an unauthorized - function or service. - - c. "Violation of permissions": Action by an entity that - exceeds the entity's system privileges by executing an - unauthorized function. - - $ thumbprint - (I) A pattern of curves formed by the ridges on the tip of a - thumb. (See: biometric authentication, fingerprint.) - - (D) ISDs SHOULD NOT use this term as a synonym for "hash result" - because that meaning mixes concepts in a potentially misleading - way. - - $ ticket - (I) A synonym for "capability". (See: Kerberos.) - - (C) A ticket is usually granted by a centralized access control - server (ticket-granting agent) to authorize access to a system - resource for a limited time. Tickets have been implemented with - symmetric cryptography, but can also be implemented as attribute - certificates using asymmetric cryptography. - - $ timing channel - See: (secondary definition under) covert channel. - - $ TLS - See: Transport Layer Security. (See: TLSP.) - - $ TLSP - See: Transport Layer Security Protocol. (See: TLS.) - - $ token - 1. (I) General usage: An object that is used to control access and - is passed between cooperating entities in a protocol that - synchronizes use of a shared resource. Usually, the entity that - currently holds the token has exclusive access to the resource. - - 2. (I) Authentication usage: A data object or a portable, user- - controlled, physical device used to verify an identity in an - authentication process. (See: authentication information, dongle.) - - 3. (I) Cryptographic usage: See: cryptographic token. - - - - - -Shirey Informational [Page 176] - -RFC 2828 Internet Security Glossary May 2000 - - - 4. (O) SET usage: "A portable device [e.g., smart card or PCMCIA - card] specifically designed to store cryptographic information and - possibly perform cryptographic functions in a secure manner." - [SET2] - - $ token backup - (I) A token management operation that stores sufficient - information in a database (e.g., in a CAW) to recreate or restore - a security token (e.g., a smart card) if it is lost or damaged. - - $ token copy - (I) A token management operation that copies all the personality - information from one security token to another. However, unlike in - a token restore operation, the second token is initialized with - its own, different local security values such as PINs and storage - keys. - - $ token management - (I) The process of initializing security tokens (e.g., see: smart - card), loading data into the tokens, and controlling the tokens - during their life cycle. May include performing key management and - certificate management functions; generating and installing PINs; - loading user personality data; performing card backup, card copy, - and card restore operations; and updating firmware. - - $ token restore - (I) A token management operation that loads a security token with - data for the purpose of recreating (duplicating) the contents - previously held by that or another token. - - $ token storage key - (I) A cryptography key used to protect data that is stored on a - security token. - - $ top CA - (I) A CA that is the highest level (i.e., is the most trusted CA) - in a certification hierarchy. (See: root.) - - $ top-level specification - (I) "A non-procedural description of system behavior at the most - abstract level; typically a functional specification that omits - all implementation details." [NCS04] (See: (discussion under) - security policy.) - - (C) A top-level specification may be descriptive or formal: - - - - - - -Shirey Informational [Page 177] - -RFC 2828 Internet Security Glossary May 2000 - - - - "Descriptive top-level specification": One that is written in a - natural language like English or an informal design notation. - - - "Formal top-level specification": One that is written in a - formal mathematical language to enable theorems to be proven that - show that the specification correctly implements a set of formal - requirements or a formal security model. (See: correctness proof.) - - $ traffic analysis - (I) Inference of information from observable characteristics of - data flow(s), even when the data is encrypted or otherwise not - directly available. Such characteristics include the identities - and locations of the source(s) and destination(s), and the - presence, amount, frequency, and duration of occurrence. (See: - wiretapping.) - - (O) "The inference of information from observation of traffic - flows (presence, absence, amount, direction, and frequency)." - [I7498 Part 2] - - $ traffic flow confidentiality - (I) A data confidentiality service to protect against traffic - analysis. - - (O) "A confidentiality service to protect against traffic - analysis." [I7498 Part 2] - - $ traffic padding - (I) "The generation of spurious instances of communication, - spurious data units, and/or spurious data within data units." - [I7498 Part 2] - - $ tranquillity property - See: (secondary definition under) Bell-LaPadula Model. - - $ Transmission Control Protocol (TCP) - (I) An Internet Standard protocol [R0793] that reliably delivers a - sequence of datagrams (discrete sets of bits) from one computer to - another in a computer network. (See: TCP/IP.) - - (C) TCP is designed to fit into a layered hierarchy of protocols - that support internetwork applications. TCP assumes it can obtain - a simple, potentially unreliable datagram service (such as the - Internet Protocol) from the lower-layer protocols. - - $ Transport Layer Security (TLS) - (I) TLS Version 1.0 is an Internet protocol [R2246] based-on and - very similar to SSL Version 3.0. (See: TLSP.) - - - -Shirey Informational [Page 178] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) The TLS protocol is misnamed, because it operates well above - the transport layer (OSI layer 4). - - $ Transport Layer Security Protocol (TLSP) - (I) An end-to-end encryption protocol(ISO Standard 10736) that - provides security services at the bottom of OSI layer 4, i.e., - directly above layer 3. (See: TLS.) - - (C) TLSP evolved directly from the SP4 protocol of SDNS. - - $ transport mode vs. tunnel mode - (I) IPsec usage: Two ways to apply IPsec protocols (AH and ESP) to - protect communications: - - - "Transport mode": The protection applies to (i.e., the IPsec - protocol encapsulates) the packets of upper-layer protocols, - the ones that are carried above IP. - - - "Tunnel mode": The protection applies to (i.e., the IPsec - protocol encapsulates) IP packets. - - (C) A transport mode security association is always between two - hosts. In a tunnel mode security association, each end may be - either a host or a gateway. Whenever either end of an IPsec - security association is a security gateway, the association is - required to be in tunnel mode. - - $ trap door - (I) A hidden computer flaw known to an intruder, or a hidden - computer mechanism (usually software) installed by an intruder, - who can activate the trap door to gain access to the computer - without being blocked by security services or mechanisms. (See: - back door, Trojan horse.) - - $ triple DES - (I) A block cipher, based on DES, that transforms each 64-bit - plaintext block by applying the Data Encryption Algorithm three - successive times, using either two or three different keys, for an - effective key length of 112 or 168 bits. [A9052] (See: DES.) - - (C) IPsec usage: The algorithm variation proposed for ESP uses a - 168-bit key, consisting of three independent 56-bit quantities - used by the Data Encryption Algorithm, and a 64-bit initialization - value. Each datagram contains an IV to ensure that each received - datagram can be decrypted even when other datagrams are dropped or - a sequence of datagrams is reordered in transit. [R1851] - - - - - -Shirey Informational [Page 179] - -RFC 2828 Internet Security Glossary May 2000 - - - $ triple-wrapped - (I) S/MIME usage: Data that has been signed with a digital - signature, and then encrypted, and then signed again. [R2634] - - $ Trojan horse - (I) A computer program that appears to have a useful function, but - also has a hidden and potentially malicious function that evades - security mechanisms, sometimes by exploiting legitimate - authorizations of a system entity that invokes the program. - - $ trust - 1. (I) Information system usage: The extent to which someone who - relies on a system can have confidence that the system meets its - specifications, i.e., that the system does what it claims to do - and does not perform unwanted functions. (See: trust level.) - - (C) "trusted vs. trustworthy": In discussing a system or system - process or object, this Glossary (and industry usage) prefers the - term "trusted" to describe a system that operates as expected, - according to design and policy. When the trust can also be - guaranteed in some convincing way, such as through formal analysis - or code review, the system is termed "trustworthy"; this differs - from the ABA Guidelines definition (see: trustworthy system). - - 2. (I) PKI usage: A relationship between a certificate user and a - CA in which the user acts according to the assumption that the CA - creates only valid digital certificates. - - (O) "Generally, an entity can be said to 'trust' a second entity - when it (the first entity) makes the assumption that the second - entity will behave exactly as the first entity expects. This trust - may apply only for some specific function. The key role of trust - in [X.509] is to describe the relationship between an entity and a - [certification] authority; an entity shall be certain that it can - trust the certification authority to create only valid and - reliable certificates." [X509] - - $ trust chain - (D) ISDs SHOULD NOT use this term as a synonym for "certification - path" because it mixes concepts in a potentially misleading way. - (See: trust.) - - $ trust-file PKI - (I) A non-hierarchical PKI in which each certificate user has a - local file (which is used by application software) of public-key - certificates that the user trusts as starting points (i.e., roots) - for certification paths. (See: hierarchical PKI, mesh PKI, root, - web of trust.) - - - -Shirey Informational [Page 180] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) For example, popular browsers are distributed with an initial - file of trusted certificates, which often are self-signed - certificates. Users can add certificates to the file or delete - from it. The file may be directly managed by the user, or the - user's organization may manage it from a centralized server. - - $ trust hierarchy - (D) ISDs SHOULD NOT use this term as a synonym for "certification - hierarchy" because this term mixes concepts (see: trust) in a - potentially misleading way and duplicates the meaning of another, - standardized term. (See: trust, web of trust.) - - $ trust level - (I) A characterization of a standard of security protection to be - met by a computer system. - - (C) The TCSEC defines eight trust levels. From the lowest to the - highest, they are D, C1, C2, B1, B2, B3, and A1. A trust level is - based not only on the presence of security mechanisms but also on - the use of systems engineering discipline to properly structure - the system and implementation analysis to ensure that the system - provides an appropriate degree of trust. - - $ trusted - See: (discussion under) trust. - - $ trusted certificate - (I) A certificate upon which a certificate user relies as being - valid without the need for validation testing; especially a - public-key certificate that is used to provide the first public - key in a certification path. (See: certification path, root - certificate, validation.) - - (C) A trusted public-key certificate might be (a) the root - certificate in a hierarchical PKI, (b) the certificate of the CA - that issued the user's own certificate in a mesh PKI, or (c) - any certificate accepted by the user in a trust-file PKI. - - $ trusted computer system - (I) Multilevel security usage: "A system that employs sufficient - hardware and software assurance measures to allow its use for - simultaneous processing of a range of sensitive or classified - information." [NCS04] (See: (discussion under) trust.) - - $ Trusted Computer System Evaluation Criteria (TCSEC) - (N) A standard for evaluating the security provided by operating - systems [CSC001, DOD1]. Informally called the "Orange Book" - - - - -Shirey Informational [Page 181] - -RFC 2828 Internet Security Glossary May 2000 - - - because of the color of its cover; first document in the Rainbow - Series. (See: Common Criteria, (usage note under) Green Book, - Orange Book, trust level.) - - $ trusted computing base (TCB) - (I) "The totality of protection mechanisms within a computer - system, including hardware, firmware, and software, the - combination of which is responsible for enforcing a security - policy." [NCS04] (See: (discussion of "trusted" under) trust.) - - $ trusted distribution - (I) "A trusted method for distributing the TCB hardware, software, - and firmware components, both originals and updates, that provides - methods for protecting the TCB from modification during - distribution and for detection of any changes to the TCB that may - occur." [NCS04] - - $ trusted key - (I) A public key upon which a user relies; especially a public key - that can be used as the first public key in a certification path. - (See: certification path, root key, validation.) - - (C) A trusted public key might be (a) the root key in a - hierarchical PKI, (b) the key of the CA that issued the user's own - certificate in a mesh PKI, or (c) any key accepted by the user in - a trust-file PKI. - - $ trusted path - (I) COMPUSEC usage: A mechanism by which a computer system user - can communicate directly and reliably with the trusted computing - base (TCB) and that can only be activated by the user or the TCB - and cannot be imitated by untrusted software within the computer. - [NCS04] - - (I) COMSEC usage: A mechanism by which a person or process can - communicate directly with a cryptographic module and that can only - be activated by the person, process, or module, and cannot be - imitated by untrusted software within the module. [FP140] - - $ trusted process - (I) A system process that has privileges that enable it to affect - the state of system security and that can, therefore, through - incorrect or malicious execution, violate the system's security - policy. (See: privileged process, (discussion of "trusted" under) - trust.) - - - - - - -Shirey Informational [Page 182] - -RFC 2828 Internet Security Glossary May 2000 - - - $ trusted subnetwork - (I) A subnetwork containing hosts and routers that trust each - other not to engage in active or passive attacks. (There also is - an assumption that the underlying communication channels--e.g., - telephone lines, or a LAN--are protected from attack by some - means.) - - $ trusted system - See: (discussion under) trust, trusted computer system, - trustworthy system. - - $ Trusted Systems Interoperability Group (TSIG) - (N) A forum of computer vendors, system integrators, and users - devoted to promoting interoperability of trusted computer systems. - TSIG meetings are open to all persons who are working in the - INFOSEC area. - - $ trustworthy system - (O) ABA usage: "Computer hardware, software, and procedures that: - (a) are reasonably secure from intrusion and misuse; (b) provide a - reasonably reliable level of availability, reliability, and - correct operation; (c) are reasonably suited to performing their - intended functions; and (d) adhere to generally accepted security - principles." [ABA] This differs somewhat from other industry - usage. (See: (discussion of "trusted vs. trustworthy" under) - trust.) - - $ TSIG - See: Trusted System Interoperability Group. - - $ tunnel - (I) A communication channel created in a computer network by - encapsulating (carrying, layering) a communication protocol's data - packets in (on top of) a second protocol that normally would be - carried above, or at the same layer as, the first one. (See: L2TP, - VPN.) - - (C) Tunneling can involve almost any OSI or TCP/IP protocol - layers; for example, a TCP connection between two hosts could - conceivably be tunneled through email messages across the - Internet. Most often, a tunnel is a logical point-to-point link-- - i.e., an OSI layer 2 connection--created by encapsulating the - layer 2 protocol in a transport protocol (such as TCP), in a - network or internetwork layer protocol (such as IP), or in another - link layer protocol. Often, encapsulation is accomplished with an - extra, intermediate protocol, i.e., a tunneling protocol (such as - L2TP) that is layered between the tunneled layer 2 protocol and - the encapsulating protocol. - - - -Shirey Informational [Page 183] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) Tunneling can move data between computers that use a protocol - not supported by the network connecting them. Tunneling also can - enable a computer network to use the services of a second network - as though the second network were a set of point-to-point links - between the first network's nodes. (See: virtual private network.) - - (O) SET usage: The name of a SET private extension that indicates - whether the CA or the payment gateway supports passing encrypted - messages to the cardholder through the merchant. If so, the - extension lists OIDs of symmetric encryption algorithms that are - supported. - - $ tunnel mode - (I) IPsec usage: See: transport mode vs. tunnel mode. - - $ two-person control - (I) The close surveillance and control of a system, process, or - materials (especially with regard to cryptography) at all times by - a minimum of two appropriately authorized persons, each capable of - detecting incorrect and unauthorized procedures with respect to - the tasks to be performed and each familiar with established - security requirements. (See: dual control, no-lone zone.) - - $ Type I cryptography - (O) A cryptographic algorithm or device approved by NSA for - protecting classified information. - - $ Type II cryptography - (O) A cryptographic algorithm or device approved by NSA for - protecting sensitive unclassified information (as specified in - section 2315 of Title 10 United States Code, or section 3502(2) of - Title 44, United States Code.) - - $ Type III cryptography - (O) A cryptographic algorithm or device approved as a Federal - Information Processing Standard. - - $ UDP - See: User Datagram Protocol. - - $ unclassified - (I) Not classified. - - $ unencrypted - (I) Not encrypted. - - - - - - -Shirey Informational [Page 184] - -RFC 2828 Internet Security Glossary May 2000 - - - $ unforgeable - (I) Cryptographic usage: The property of a cryptographic data - structure (i.e., a data structure that is defined using one or - more cryptographic functions) that makes it computationally - infeasible to construct (i.e., compute) an unauthorized but - correct value of the structure without having knowledge of one of - more keys. (E.g., see: digital certificate.) - - (C) This definition is narrower than general English usage, where - "unforgeable" means unable to be fraudulently created or - duplicated. In that broader sense, anyone can forge a digital - certificate containing any set of data items whatsoever by - generating the to-be-signed certificate and signing it with any - private key whatsoever. But for PKI purposes, the forged data - structure is invalid if it is not signed with the true private key - of the claimed issuer; thus, the forgery will be detected when a - certificate user uses the true public key of the claimed issuer to - verify the signature. - - $ uniform resource identifier (URI) - (I) A type of formatted identifier that encapsulates the name of - an Internet object, and labels it with an identification of the - name space, thus producing a member of the universal set of names - in registered name spaces and of addresses referring to registered - protocols or name spaces. [R1630] - - (C) URIs are used in HTML to identify the target of hyperlinks. In - common practice, URIs include uniform resource locators [R2368] - and relative URLs, and may be URNs. [R1808] - - $ uniform resource locator (URL) - (I) A type of formatted identifier that describes the access - method and location of an information resource object on the - Internet. [R1738] - - (C) A URL is a URI that provides explicit instructions on how to - access the named object. For example, - "ftp://bbnarchive.bbn.com/foo/bar/picture/cambridge.zip" is a URL. - The part before the colon specifies the access scheme or protocol, - and the part after the colon is interpreted according to that - access method. Usually, two slashes after the colon indicate the - host name of a server (written as a domain name). In an FTP or - HTTP URL, the host name is followed by the path name of a file on - the server. The last (optional) part of a URL may be either a - fragment identifier that indicates a position in the file, or a - query string. - - - - - -Shirey Informational [Page 185] - -RFC 2828 Internet Security Glossary May 2000 - - - $ uniform resource name (URN) - (I) A URI that has an institutional commitment to persistence and - availability. - - $ untrusted process - (I) A system process that is not able to affect the state of - system security through incorrect or malicious operation, usually - because its operation is confined by a security kernel. (See: - trusted process.) - - $ UORA - See: user-PIN ORA. - - $ update - See: certificate update and key update. - - $ URI - See: uniform resource identifier. - - $ URL - See: uniform resource locator. - - $ URN - See: uniform resource name. - - $ user - (I) A person, organization entity, or automated process that - accesses a system, whether authorized to do so or not. (See: - [R2504].) - - (C) Any ISD that uses this term SHOULD provide an explicit - definition, because this term is used in many ways and can easily - be misunderstood. - - $ User Datagram Protocol (UDP) - (I) An Internet Standard protocol [R0768] that provides a datagram - mode of packet-switched computer communication in an internetwork. - - (C) UDP is a transport layer protocol, and it assumes that IP is - the underlying protocol. UDP enables application programs to send - transaction-oriented data to other programs with minimal protocol - mechanism. UDP does not provide reliable delivery, flow control, - sequencing, or other end-to-end services that TCP provides. - - $ user identifier - (I) A character string or symbol that is used in a system to - uniquely name a specific user or group of users. - - - - -Shirey Informational [Page 186] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) Often verified by a password in an authentication process. - - $ user PIN - (O) MISSI usage: One of two personal identification numbers that - control access to the functions and stored data of a FORTEZZA PC - card. Knowledge of the user PIN enables the card user to perform - the FORTEZZA functions that are intended for use by an end user. - (See: SSO PIN.) - - $ user-PIN ORA (UORA) - (O) A MISSI organizational RA that operates in a mode in which the - ORA performs only the subset of card management functions that are - possible with knowledge of the user PIN for a FORTEZZA PC card. - (See: no-PIN ORA, SSO-PIN ORA.) - - $ usurpation - See: (secondary definition under) threat consequence. - - $ UTCTime - (N) The ASN.1 data type "UTCTime" contains a calendar date - (YYMMDD) and a time to a precision of either one minute (HHMM) or - one second (HHMMSS), where the time is either (a) Coordinated - Universal Time or (b) the local time followed by an offset that - enables Coordinated Universal Time to be calculated. Note: UTCTime - has the Year 2000 problem. (See: Coordinated Universal Time, - GeneralizedTime.) - - $ v1 certificate - (C) Ambiguously refers to either an X.509 public-key certificate - in its version 1 format, or an X.509 attribute certificate in its - version 1 format. However, many people who use this term are not - aware that X.509 specifies attribute certificates that do not - contain a public key. Therefore, ISDs MAY use this term as an - abbreviation for "version 1 X.509 public-key certificate", but - only after using the full term at the first instance. - - (D) ISDs SHOULD NOT use this term as an abbreviation for "version - 1 X.509 attribute certificate". - - $ v1 CRL - (I) An abbreviation for "X.509 CRL in version 1 format". - - (C) ISDs should use this abbreviation only after using the full - term at its first occurrence and defining the abbreviation. - - $ v2 certificate - (I) An abbreviation for "X.509 public-key certificate in version 2 - format". - - - -Shirey Informational [Page 187] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) ISDs should use this abbreviation only after using the full - term at its first occurrence and defining the abbreviation. - - $ v2 CRL - (I) An abbreviation for "X.509 CRL in version 2 format". - - (C) ISDs should use this abbreviation only after using the full - term at its first occurrence and defining the abbreviation. - - $ v3 certificate - (I) An abbreviation for "X.509 public-key certificate in version 3 - format". - - (C) ISDs should use this abbreviation only after using the full - term at its first occurrence and defining the abbreviation. - - $ valid certificate - (I) A digital certificate for which the binding of the data items - can be trusted; one that can be validated successfully. (See: - validate vs. verify.) - - $ valid signature - (D) ISDs SHOULD NOT use this term; instead, use "authentic - signature". This Glossary recommends saying "validate the - certificate" and "verify the signature"; therefore, it would be - inconsistent to say that a signature is "valid". (See: validate - vs. verify.) - - $ validate vs. verify - (C) The PKI community uses words inconsistently when describing - what a certificate user does to make certain that a digital - certificate can be trusted. Usually, we say "verify the signature" - but say "validate the certificate"; i.e., we "verify" atomic - truths but "validate" data structures, relationships, and systems - that are composed of or depend on verified items. Too often, - however, verify and validate are used interchangeably. - - ISDs SHOULD comply with the following two rules to ensure - consistency and to align Internet security terminology with - ordinary English: - - - Rule 1: Use "validate" when referring to a process intended to - establish the soundness or correctness of a construct. (E.g., - see: certificate validation.) - - - Rule 2: Use "verify" when referring to a process intended to - test or prove the truth or accuracy of a fact or value. (E.g., - see: authenticate.) - - - -Shirey Informational [Page 188] - -RFC 2828 Internet Security Glossary May 2000 - - - The rationale for Rule 1 is that "valid" derives from a word that - means "strong" in Latin. Thus, to validate means to make sure that - a construction is sound. A certificate user validates a public-key - certificate to establish trust in the binding that the certificate - asserts between an identity and a key. (To validate can also mean - to officially approve something; e.g., NIST validates - cryptographic modules for conformance with FIPS PUB 140-1.) - - The rationale for Rule 2 is that "verify" derives from a word that - means "true" in Latin. Thus, to verify means to prove the truth of - an assertion by examining evidence or performing tests. To verify - an identity, an authentication process examines identification - information that is presented or generated. To validate a - certificate, a certificate user verifies the digital signature on - the certificate by performing calculations; verifies that the - current time is within the certificate's validity period; and may - need to validate a certification path involving additional - certificates. - - $ validation - See: validate vs. verify. - - $ validity period - (I) A data item in a digital certificate that specifies the time - period for which the binding between data items (especially - between the subject name and the public key value in a public-key - certificate) is valid, except if the certificate appears on a CRL - or the key appears on a CKL. - - $ value-added network (VAN) - (I) A computer network or subnetwork (which is usually a - commercial enterprise) that transmits, receives, and stores EDI - transactions on behalf of its customers. - - (C) A VAN may also provide additional services, ranging from EDI - format translation, to EDI-to-FAX conversion, to integrated - business systems. - - $ VAN - See: value-added network. - - $ verification - 1. System verification: The process of comparing two levels of - system specification for proper correspondence, such as comparing - a security policy with a top-level specification, a top-level - specification with source code, or source code with object code. - [NCS04] - - - - -Shirey Informational [Page 189] - -RFC 2828 Internet Security Glossary May 2000 - - - 2. Identification verification: Presenting information to - establish the truth of a claimed identity. - - $ verify - See: validate vs. verify. - - $ violation - See: security violation. - - $ virtual private network (VPN) - (I) A restricted-use, logical (i.e., artificial or simulated) - computer network that is constructed from the system resources of - a relatively public, physical (i.e., real) network (such as the - Internet), often by using encryption (located at hosts or - gateways), and often by tunneling links of the virtual network - across the real network. - - (C) For example, if a corporation has LANs at several different - sites, each connected to the Internet by a firewall, the - corporation could create a VPN by (a) using encrypted tunnels to - connect from firewall to firewall across the Internet and (b) not - allowing any other traffic through the firewalls. A VPN is - generally less expensive to build and operate than a dedicated - real network, because the virtual network shares the cost of - system resources with other users of the real network. - - $ virus - (I) A hidden, self-replicating section of computer software, - usually malicious logic, that propagates by infecting--i.e., - inserting a copy of itself into and becoming part of--another - program. A virus cannot run by itself; it requires that its host - program be run to make the virus active. - - $ VPN - See: virtual private network. - - $ vulnerability - (I) A flaw or weakness in a system's design, implementation, or - operation and management that could be exploited to violate the - system's security policy. - - (C) Most systems have vulnerabilities of some sort, but this does - not mean that the systems are too flawed to use. Not every threat - results in an attack, and not every attack succeeds. Success - depends on the degree of vulnerability, the strength of attacks, - and the effectiveness of any countermeasures in use. If the - attacks needed to exploit a vulnerability are very difficult to - carry out, then the vulnerability may be tolerable. If the - - - -Shirey Informational [Page 190] - -RFC 2828 Internet Security Glossary May 2000 - - - perceived benefit to an attacker is small, then even an easily - exploited vulnerability may be tolerable. However, if the attacks - are well understood and easily made, and if the vulnerable system - is employed by a wide range of users, then it is likely that there - will be enough benefit for someone to make an attack. - - $ W3 - See: World Wide Web. - - $ war dialer - (I) A computer program that automatically dials a series of - telephone numbers to find lines connected to computer systems, and - catalogs those numbers so that a cracker can try to break into the - systems. - - $ Wassenaar Arrangement - (N) The Wassenaar Arrangement on Export Controls for Conventional - Arms and Dual-Use Goods and Technologies is a global, multilateral - agreement approved by 33 countries in July 1996 to contribute to - regional and international security and stability, by promoting - information exchange concerning, and greater responsibility in, - transfers of arms and dual-use items, thus preventing - destabilizing accumulations. (See: International Traffic in Arms - Regulations.) - - (C) The Arrangement began operations in September 1996. The - participating countries are Argentina, Australia, Austria, - Belgium, Bulgaria, Canada, Czech Republic, Denmark, Finland, - France, Germany, Greece, Hungary, Ireland, Italy, Japan, - Luxembourg, Netherlands, New Zealand, Norway, Poland, Portugal, - Republic of Korea, Romania, Russian Federation, Slovak Republic, - Spain, Sweden, Switzerland, Turkey, Ukraine, United Kingdom, and - United States. Participants meet on a regular basis in Vienna, - where the Arrangement has its headquarters. - - Participating countries seek through their national policies to - ensure that transfers do not contribute to the development or - enhancement of military capabilities that undermine the goals of - the arrangement, and are not diverted to support such - capabilities. The countries maintain effective export controls for - items on the agreed lists, which are reviewed periodically to - account for technological developments and experience gained. - Through transparency and exchange of views and information, - suppliers of arms and dual-use items can develop common - understandings of the risks associated with their transfer and - assess the scope for coordinating national control policies to - combat these risks. Members provide semi-annual notification of - arms transfers, covering seven categories derived from the UN - - - -Shirey Informational [Page 191] - -RFC 2828 Internet Security Glossary May 2000 - - - Register of Conventional Arms. Members also report transfers or - denials of transfers of certain controlled dual-use items. - However, the decision to transfer or deny transfer of any item is - the sole responsibility of each participating country. All - measures undertaken with respect to the arrangement are in - accordance with national legislation and policies and are - implemented on the basis of national discretion. - - $ watermarking - See: digital watermarking. - - $ web of trust - (O) PGP usage: A trust-file PKI technique used in PGP for building - a file of validated public keys by making personal judgments about - being able to trust certain people to be holding properly - certified keys of other people. (See: certification hierarchy, - mesh PKI.) - - $ web server - (I) A software process that runs on a host computer connected to - the Internet to respond to HTTP requests for documents from client - web browsers. - - $ web vs. Web - 1. (I) Capitalized: ISDs SHOULD capitalize "Web" when using the - term (as either a noun or an adjective) to refer specifically to - the World Wide Web. (Similarly, see: internet vs. Internet.) - - 2. (C) Not capitalized: ISDs SHOULD NOT capitalize "web" when - using the term (usually as an adjective) to refer generically to - technology--such as web browsers, web servers, HTTP, and HTML-- - that is used in the Web or similar networks. - - (C) IETF documents SHOULD spell out "World Wide Web" fully at the - first instance of usage and SHOULD Use "Web" and "web" especially - carefully where confusion with the PGP "web of trust" is possible. - - $ wiretapping - (I) An attack that intercepts and accesses data and other - information contained in a flow in a communication system. - - (C) Although the term originally referred to making a mechanical - connection to an electrical conductor that links two nodes, it is - now used to refer to reading information from any sort of medium - used for a link or even directly from a node, such as gateway or - subnetwork switch. - - - - - -Shirey Informational [Page 192] - -RFC 2828 Internet Security Glossary May 2000 - - - (C) "Active wiretapping" attempts to alter the data or otherwise - affect the flow; "passive wiretapping" only attempts to observe - the flow and gain knowledge of information it contains. (See: - active attack, end-to-end encryption, passive attack.) - - $ work factor - (I) General security usage: The estimated amount of effort or time - that can be expected to be expended by a potential intruder to - penetrate a system, or defeat a particular countermeasure, when - using specified amounts of expertise and resources. - - (I) Cryptography usage: The estimated amount of computing time and - power needed to break a cryptographic system. - - $ World Wide Web ("the Web", WWW, W3) - (N) The global, hypermedia-based collection of information and - services that is available on Internet servers and is accessed by - browsers using Hypertext Transfer Protocol and other information - retrieval mechanisms. (See: web vs. Web, [R2084].) - - $ worm - (I) A computer program that can run independently, can propagate a - complete working version of itself onto other hosts on a network, - and may consume computer resources destructively. (See: Morris - Worm, virus.) - - $ wrap - (O) To use cryptography to provide data confidentiality service - for a data object. (See: encrypt, seal.) - - (D) ISDs SHOULD NOT use this term with this definition because it - duplicates the meaning of other, standard terms. Instead, use - "encrypt" or use a term that is specific with regard to the - mechanism used. - - $ WWW - See: World Wide Web. - - $ X.400 - (N) An ITU-T Recommendation [X400] that is one part of a joint - ITU-T/ISO multi-part standard (X.400-X.421) that defines the - Message Handling Systems. (The ISO equivalent is IS 10021, parts - 1-7.) (See: Message Handling Systems.) - - $ X.500 - $ X.500 Directory - (N) An ITU-T Recommendation [X500] that is one part of a joint - ITU-T/ISO multi-part standard (X.500-X.525) that defines the X.500 - - - -Shirey Informational [Page 193] - -RFC 2828 Internet Security Glossary May 2000 - - - Directory, a conceptual collection of systems that provide - distributed directory capabilities for OSI entities, processes, - applications, and services. (The ISO equivalent is IS 9594-1 and - related standards, IS 9594-x.) (See: directory vs. Directory, - X.509.) - - (C) The X.500 Directory is structured as a tree (the Directory - Information Tree), and information is stored in directory entries. - Each entry is a collection of information about one object, and - each object has a DN. A directory entry is composed of attributes, - each with a type and one or more values. For example, if a PKI - uses the Directory to distribute certificates, then the X.509 - public-key certificate of an end user is normally stored as a - value of an attribute of type "userCertificate" in the Directory - entry that has the DN that is the subject of the certificate. - - $ X.509 - (N) An ITU-T Recommendation [X509] that defines a framework to - provide and support data origin authentication and peer entity - authentication services, including formats for X.509 public-key - certificates, X.509 attribute certificates, and X.509 CRLs. (The - ISO equivalent is IS 9498-4.) (See: X.500.) - - (C) X.509 describes two levels of authentication: simple - authentication based on a password, and strong authentication - based on a public-key certificate. - - $ X.509 attribute certificate - (N) An attribute certificate in the version 1 (v1) format defined - by X.509. (The v1 designation for an X.509 attribute certificate - is disjoint from the v1 designation for an X.509 public-key - certificate, and from the v1 designation for an X.509 CRL.) - - (C) An X.509 attribute certificate has a subject field, but the - attribute certificate is a separate data structure from that - subject's public-key certificate. A subject may have multiple - attribute certificates associated with each of its public-key - certificates, and an attribute certificate may be issued by a - different CA than the one that issued the associated public-key - certificate. - - (C) An X.509 attribute certificate contains a sequence of data - items and has a digital signature that is computed from that - sequence. In addition to the signature, an attribute certificate - contains items 1 through 9 listed below: - - - - - - -Shirey Informational [Page 194] - -RFC 2828 Internet Security Glossary May 2000 - - - 1. version Identifies v1. - 2. subject Is one of the following: - 2a. baseCertificateID - Issuer and serial number of an - X.509 public-key certificate. - 2b. subjectName - DN of the subject. - 3. issuer DN of the issuer (the CA who signed). - 4. signature OID of algorithm that signed the cert. - - 5. serialNumber Certificate serial number; - an integer assigned by the issuer. - 6. attCertValidityPeriod Validity period; a pair of UTCTime - values: "not before" and "not after". - 7. attributes Sequence of attributes describing the - subject. - 8. issuerUniqueId Optional, when a DN is not sufficient. - 9. extensions Optional. - - $ X.509 authority revocation list - (N) An ARL in one of the formats defined by X.509--version 1 (v1) - or version 2 (v2). A specialized kind of certificate revocation - list. - - $ X.509 certificate - (N) Either an X.509 public-key certificate or an X.509 attribute - certificate. - - (C) This Glossary uses the term with the precise meaning - recommended here. However, some who use the term may not be aware - that X.509 specifies attribute certificates that do not contain a - public key. Even among those who are aware, this term is commonly - used as an abbreviation to mean "X.509 public-key certificate". - ISDs MAY use the term as an abbreviation for "X.509 public-key - certificate", but only after using the full term at the first - instance. - - (D) ISDs SHOULD NOT use this term as an abbreviation to mean - "X.509 attribute certificate". - - $ X.509 certificate revocation list (CRL) - (N) A CRL in one of the formats defined by X.509--version 1 (v1) - or version 2 (v2). (The v1 and v2 designations for an X.509 CRL - are disjoint from the v1 and v2 designations for an X.509 public- - key certificate, and from the v1 designation for an X.509 - attribute certificate.) (See: certificate revocation.) - - (C) ISDs SHOULD NOT refer to an X.509 CRL as a digital - certificate, but note that an X.509 CRL does meet this Glossary's - definition of "digital certificate". Like a digital certificate, - - - -Shirey Informational [Page 195] - -RFC 2828 Internet Security Glossary May 2000 - - - an X.509 CRL makes an assertion and is signed by a CA. But instead - of binding a key or other attributes to a subject, an X.509 CRL - asserts that certain previously-issued X.509 certificates have - been revoked. - - (C) An X.509 CRL contains a sequence of data items and has a - digital signature computed on that sequence. In addition to the - signature, both v1 and v2 contain items 2 through 6b listed below. - Version 2 contains item 1 and may optionally contain 6c and 7. - - 1. version Optional. If present, identifies v2. - 2. signature OID of the algorithm that signed CRL. - 3. issuer DN of the issuer (the CA who signed). - 4. thisUpdate A UTCTime value. - 5. nextUpdate A UTCTime value. - 6. revokedCertificates 3-tuples of 6a, 6b, and (optional) 6c: - 6a. userCertificate A certificate's serial number. - 6b. revocationDate UTCTime value for the revocation date. - 6c. crlEntryExtensions Optional. - 7. crlExtensions Optional. - - $ X.509 public-key certificate - (N) A public-key certificate in one of the formats defined by - X.509--version 1 (v1), version 2 (v2), or version 3 (v3). (The v1 - and v2 designations for an X.509 public-key certificate are - disjoint from the v1 and v2 designations for an X.509 CRL, and - from the v1 designation for an X.509 attribute certificate.) - - (C) An X.509 public-key certificate contains a sequence of data - items and has a digital signature computed on that sequence. In - addition to the signature, all three versions contain items 1 - through 7 listed below. Only v2 and v3 certificates may also - contain items 8 and 9, and only v3 may contain item 10. - - 1. version Identifies v1, v2, or v3. - 2. serialNumber Certificate serial number; - an integer assigned by the issuer. - 3. signature OID of algorithm that was used to - sign the certificate. - 4. issuer DN of the issuer (the CA who signed). - 5. validity Validity period; a pair of UTCTime - values: "not before" and "not after". - 6. subject DN of entity who owns the public key. - 7. subjectPublicKeyInfo Public key value and algorithm OID. - 8. issuerUniqueIdentifier Defined for v2, v3; optional. - 9. subjectUniqueIdentifier Defined for v2, v2; optional. - 10. extensions Defined only for v3; optional. - - - - -Shirey Informational [Page 196] - -RFC 2828 Internet Security Glossary May 2000 - - - $ XTACACS - See: (secondary definition under) Terminal Access Controller (TAC) - Access Control System. - - $ Yellow Book - (D) ISDs SHOULD NOT use this term as a synonym for "Computer - Security Requirements: Guidance for Applying the Department of - Defense Trusted Computer System Evaluation Criteria in Specific - Environments" [CSC3]. Instead, use the full proper name of the - document or, in subsequent references, a conventional - abbreviation. (See: (usage note under) Green Book, Rainbow - Series.) - - $ zeroize - (I) Use erasure or other means to render stored data unusable and - unrecoverable, particularly a key stored in a cryptographic module - or other device. - - (O) Erase electronically stored data by altering the contents of - the data storage so as to prevent the recovery of the data. - [FP140] - -4. References - - This Glossary focuses on the Internet Standards Process. Therefore, - this set of references emphasizes international, governmental, and - industry standards documents; only a few other texts are listed. RFCs - are listed, but not Internet-Drafts, because the latter are not an - archival document series and should not be cited or quoted in an RFC. - - [A3092] American National Standards Institute, "American National - Standard Data Encryption Algorithm", ANSI X3.92-1981, 30 Dec - 1980. - - [A9009] ---, "Financial Institution Message Authentication - (Wholesale)", ANSI X9.9-1986, 15 Aug 1986. - - [A9017] ---, "Financial Institution Key Management (Wholesale)", - X9.17, 4 Apr 1985. [Defines procedures for the manual and - automated management of keying material and uses DES to - provide key management for a variety of operational - environments.] - - [A9042] ---, "Public key Cryptography for the Financial Service - Industry: Agreement of Symmetric Keys Using Diffie-Hellman - and MQV Algorithms", X9.42, 29 Jan 1999. - - - - - -Shirey Informational [Page 197] - -RFC 2828 Internet Security Glossary May 2000 - - - [A9052] ---, "Triple Data Encryption Algorithm Modes of Operation", - X9.52-1998, ANSI approval 9 Nov 1998. - - [A9062] ---, "Public Key Cryptography for the Financial Services - Industry: The Elliptic Curve Digital Signature Algorithm - (ECDSA)", X9.62-1998, ANSI approval 7 Jan 1999. - - [ABA] American Bar Association, "Digital Signature Guidelines: - Legal Infrastructure for Certification Authorities and - Secure Electronic Commerce", Chicago, IL, 1 Aug 1996. - - [ACM] Association for Computing Machinery, "Communications of the - ACM", Jul 1998 issue with: Minerva M. Yeung, "Digital - Watermarking"; Nasir Memom and Ping Wah Wong, "Protecting - Digital Media Content"; and Scott Craver, Boon-Lock Yeo, and - Minerva Yeung, "Technical Trials and Legal Tribulations". - - [Army] U.S. Army Corps of Engineers, "Electromagnetic Pulse (EMP) - and Tempest Protection for Facilities", EP 1110-3-2, 31 Dec - 1990. - - [B7799] British Standards Institution, "Information Security - Management, Part 1: Code of Practice for Information - Security Management", BS 7799-1:1999, effective 15 May 1999. - - ---, ---, "Part 2: Specification for Information Security - Management Systems", BS 7799-2:1999, effective 15 May 1999. - - [Bell] D. E. Bell and L. J. LaPadula, "Secure Computer Systems: - Mathematical Foundations and Model", M74-244, The MITRE - Corporation, Bedford, MA, May 1973. (Available as AD-771543, - National Technical Information Service, Springfield, VA.) - - [CCIB] Common Criteria Implementation Board, "Common Criteria for - Information Technology Security Evaluation, Part 1: - Introduction and General Model", ver. 2.1, CCIB-99-01, Aug - 1999. - - [CIPSO] Trusted Systems Interoperability Working Group, "Common IP - Security Option", ver. 2.3, 9 Mar 1993. [A "work in - progress" that is probably defunct.] - - [CSC1] U.S. Department of Defense Computer Security Center, - "Department of Defense Trusted Computer System Evaluation - Criteria", CSC-STD-001-83, 15 Aug 1983. (Superseded by - [DOD1].) - - - - - -Shirey Informational [Page 198] - -RFC 2828 Internet Security Glossary May 2000 - - - [CSC2] ---, "Department of Defense Password Management Guideline", - CSC-STD-002-85, 12 Apr 1985. - - [CSC3] ---, "Computer Security Requirements: Guidance for Applying - the Department of Defense Trusted Computer System Evaluation - Criteria in Specific Environments", CSC-STD-003-85, 25 Jun - 1985. - - [CSOR] U.S. Department of Commerce, "General Procedures for - Registering Computer Security Objects", National Institute - of Standards Interagency Report 5308, Dec 1993. - - [Denn] D. E. Denning, "A Lattice Model of Secure Information Flow", - in "Communications of the ACM", vol. 19, no. 5, May 1976, - pp. 236-243. - - [DH76] W. Diffie and M. H. Hellman, "New Directions in - Cryptography" in "IEEE Transactions on Information Theory", - vol. IT-22, no. 6, Nov 1976, pp. 644-654. - - [DOD1] U.S. Department of Defense, "Department of Defense Trusted - Computer System Evaluation Criteria", DoD 5200.28-STD, 26 - Dec 1985. (Supersedes [CSC1].) - - [DOD2] ---, Directive 5200.28, "Security Requirements for Automated - Information Systems (AISs)", 21 Mar 1988. - - [DOD3] ---, "X.509 Certificate Policy", ver. 2, Mar 1999. - - [DOD4] ---, "NSA Key Recovery Assessment Criteria", 8 Jun 1998. - - [ElGa] T. El Gamal, "A Public-Key Cryptosystem and a Signature - Scheme Based on Discrete Logarithms" in "IEEE Transactions - on Information Theory", vol. IT-31, no. 4, 1985, pp. 469- - 472. - - [EMV1] Europay International S.A., MasterCard International - Incorporated, and Visa International Service Association, - "EMV '96 Integrated Circuit Card Specification for Payment - Systems", ver. 3.1.1, 31 May 1998. - - [EMV2] ---, "EMV '96 Integrated Circuit Card Terminal Specification - for Payment Systems", ver. 3.1.1, 31 May 1998. - - [EMV3] ---, EMV '96 Integrated Circuit Card Application - Specification for Payment Systems", ver. 3.1.1, 31 May 1998. - - - - - -Shirey Informational [Page 199] - -RFC 2828 Internet Security Glossary May 2000 - - - [For94] W. Ford, "Computer Communications Security: Principles, - Standard Protocols and Techniques", ISBN 0-13-799453-2, - 1994. - - [For97] W. Ford and M. Baum, "Secure Electronic Commerce: Building - the Infrastructure for Digital Signatures and Encryption", - ISBN 0-13-476342-4, 1994. - - [FP031] U.S. Department of Commerce, "Guidelines for Automatic Data - Processing Physical Security and Risk Management", Federal - Information Processing Standards Publication (FIPS PUB) 31, - Jun 1974. - - [FP039] ---, "Glossary for Computer Systems Security", FIPS PUB 39, - 15 Feb 1976. - - [FP046] ---, "Data Encryption Standard (DES)", FIPS PUB 46-2, 30 Dec - 1993. - - [FP081] ---, "DES Modes of Operation", FIPS PUB 81, 2 Dec 1980. - - [FP102] ---, "Guideline for Computer Security Certification and - Accreditation", FIPS PUB 102, 27 Sep 1983. - - [FP113] ---, "Computer Data Authentication", FIPS PUB 113, 30 May - 1985. - - [FP140] ---, "Security Requirements for Cryptographic Modules", FIPS - PUB 140-1, 11 Jan 1994. - - [FP151] ---, "Portable Operating System Interface (POSIX)--System - Application Program Interface [C Language]", FIPS PUB 151-2, - 12 May 1993 - - [FP180] ---, "Secure Hash Standard", FIPS PUB 180-1, 17 Apr 1995. - - [FP185] ---, "Escrowed Encryption Standard", FIPS PUB 185, 9 Feb - 1994. - - [FP186] ---, "Digital Signature Standard (DSS)", FIPS PUB 186, 19 - May 1994. - - [FP188] ---, "Standard Security Label for Information Transfer", - FIPS PUB 188, 6 Sep 1994. - - [FPDAM] Collaborative ITU and ISO/IEC meeting on the Directory, - "Final Proposed Draft Amendment on Certificate Extensions", - April 1999. (This draft proposes changes to [X.509].) - - - -Shirey Informational [Page 200] - -RFC 2828 Internet Security Glossary May 2000 - - - [FPKI] U.S. Department of Commerce, "Public Key Infrastructure - (PKI) Technical Specifications: Part A--Technical Concept of - Operations", National Institute of Standards, 4 Sep 1998. - - [I3166] International Standards Organization, "Codes for the - Representation of Names of countries and Their Subdivisions - --Part 1: Country Codes", ISO 3166-1:1997. - - ---, --- "Part 2: Country Subdivision Codes", ISO/DIS 3166- - 2. - - ---, --- "Part 3: Codes for Formerly Used Names of - Countries", ISO/DIS 3166-3. - - [I7498] ---, "Information Processing Systems--Open Systems - Interconnection Reference Model--[Part 1:] Basic Reference - Model", ISO/IEC 7498-1. (Equivalent to ITU-T Recommendation - X.200.) - - ---, --- "Part 2: Security Architecture", ISO/IEC 7499-2. - - ---, --- "Part 4: Management Framework", ISO/IEC 7498-4. - - [I7812] ---, "Identification cards--Identification of Issuers--Part - 1: Numbering System", ISO/IEC 7812-1:1993 - - ---, --- "Part 2: Application and Registration Procedures", - ISO/IEC 7812-2:1993. - - [I9945] ---, "Portable Operating System Interface for Computer - Environments", ISO/IEC 9945-1:1990. - - [I15408] ---, "Information Technology--Security Techniques-- - Evaluation criteria for IT Security--Part 1: Introduction - and General Model", ISO/IEC 15408-1:1999. - - [ITSEC] "Information Technology Security Evaluation Criteria - (ITSEC): Harmonised Criteria of France, Germany, the - Netherlands, and the United Kingdom", ver. 1.2, U.K. - Department of Trade and Industry, Jun 1991. - - [Kahn] David Kahn, "The Codebreakers: The Story of Secret Writing", - The Macmillan Company, New York, 1967. - - [Knuth] D. E. Knuth, Chapter 3 ("Random Numbers") in Volume 2 - ("Seminumerical Algorithms") of "The Art of Computer - Programming", Addison-Wesley, Reading, MA, 1969. - - - - -Shirey Informational [Page 201] - -RFC 2828 Internet Security Glossary May 2000 - - - [Kuhn] Markus G. Kuhn and Ross J. Anderson, "Soft Tempest: Hidden - Data Transmission Using Electromagnetic Emanations", in - David Aucsmith, ed., "Information Hiding, Second - International Workshop, IH'98", Portland, Oregon, USA, 15-17 - Apr 1998, LNCS 1525, Springer-Verlag, ISBN 3-540-65386-4, - pp. 124-142. - - [MISPC] U.S. Department of Commerce, "Minimum Interoperability - Specification for PKI Components (MISPC), Version 1", - National Institute of Standards Special Publication 800-15, - Sep 1997. - - [NCS01] National Computer Security Center, "A Guide to Understanding - Audit in Trusted Systems", NCSC-TG-001, 1 Jun 1988. (Part of - the Rainbow Series.) - - [NCS04] ---, "Glossary of Computer Security Terms", NCSC-TG-004, - ver. 1, 21 Oct 1988. (Part of the Rainbow Series.) - - [NCS05] ---, "Trusted Network Interpretation of the Trusted Computer - System Evaluation Criteria", NCSC-TG-005, ver. 1, 31 Jul - 1987. (Part of the Rainbow Series.) - - [NCS25] ---, "A Guide to Understanding Data Remanence in Automated - Information Systems", NCSC-TG-025, ver. 2, Sep 1991. (Part - of the Rainbow Series.) - - [NIST] National Institute of Standards and Technology, "SKIPJACK - and KEA Algorithm Specifications", ver. 2, 29 May 1998. - (http://csrc.nist.gov/encryption/skipjack-kea.htm) - - [PGP] Simson Garfinkel, "PGP: Pretty Good Privacy", O'Reilly & - Associates, Inc., Sebastopol, CA, 1995. - - [PKCS] Burton S. Kaliski, Jr., "An Overview of the PKCS Standards", - RSA Data Security, Inc., 3 Jun 1991. - - [PKC07] RSA Laboratories, "PKCS #7: Cryptographic Message Syntax - Standard", ver. 1.5, RSA Laboratories Technical Note, 1 Nov - 1993. - - [PKC10] ---, "PKCS #10: Certification Request Syntax Standard", ver. - 1.0, RSA Laboratories Technical Note, 1 Nov 1993. - - [PKC11] ---, "PKCS #11: Cryptographic Token Interface Standard", - ver. 1.0, 28 Apr 1995. - - - - - -Shirey Informational [Page 202] - -RFC 2828 Internet Security Glossary May 2000 - - - [R0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, August - 1980. - - [R0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September - 1981. - - [R0792] Postel, J., "Internet Control Message Protocol", STD 5, RFC - 792, September 1981. [See: RFC 1885.] - - [R0793] Postel, J., ed., "Transmission Control Protocol", STD 7, RFC - 793, September 1981. - - [R0821] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC - 821, August 1982. - - [R0822] Crocker, D., "Standard for the Format of ARPA Internet Text - Messages", STD 11, RFC 822, August 1982. - - [R0854] Postel, J. and J. Reynolds, "TELNET Protocol Specification", - STD 8, RFC 854, May 1983. - - [R0959] Postel, J. and J. Reynolds, "File Transfer Protocol (FTP)", - STD 9, RFC 959, October 1985. - - [R1034] Mockapetris, P., "Domain Names--Concepts and Facilities", - STD 13, RFC 1034, November 1987. - - [R1157] Case, J., Fedor, M., Schoffstall, M. and J. Davin, "A Simple - Network Management Protocol (SNMP)" [version 1], STD 15, RFC - 1157, May 1990. - - [R1208] Jacobsen O. and D. Lynch, "A Glossary of Networking Terms", - RFC 1208, March 1991. - - [R1319] Kaliski, B., "The MD2 Message-Digest Algorithm", RFC 1319, - April 1992. - - [R1320] Rivest, R., "The MD4 Message-Digest Algorithm", RFC 1320, - April 1992. - - [R1321] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, - April 1992. - - [R1334] Lloyd, B. and W. Simpson, "PPP Authentication Protocols", - RFC 1334, October 1992. - - [R1413] St. Johns, M., "Identification Protocol", RFC 1413, February - 1993. - - - -Shirey Informational [Page 203] - -RFC 2828 Internet Security Glossary May 2000 - - - [R1421] Linn, J., "Privacy Enhancement for Internet Electronic Mail, - Part I: Message Encryption and Authentication Procedures", - RFC 1421, February 1993. - - [R1422] Kent, S., "Privacy Enhancement for Internet Electronic Mail, - Part II: Certificate-Based Key Management", RFC 1422, - February 1993. - - [R1455] Eastlake, D., "Physical Link Security Type of Service", RFC - 1455, May 1993. - - [R1457] Housley, R., "Security Label Framework for the Internet", - RFC 1457, May 1993. - - [R1492] Finseth, C., "An Access Control Protocol, Sometimes Called - TACACS", RFC 1492, July 1993. - - [R1507] Kaufman, C., "DASS: Distributed Authentication Security - Service", RFC 1507, September 1993. - - [R1510] Kohl, J. and C. Neuman, "The Kerberos Network Authentication - Service (V5)", RFC 1510, September 1993. - - [R1591] Kohl, J. and C. Neuman, "Domain Name System Structure and - Delegation", March 1994. - - [R1630] Berners-Lee, T., "Universal Resource Identifiers in WWW", - RFC 1630, June 1994. - - [R1661] Simpson, W., ed., " The Point-to-Point Protocol (PPP)", STD - 51, RFC 1661, July 1994. - - [R1731] Myers, J., "IMAP4 Authentication Mechanisms", RFC 1731, - December 1994. - - [R1734] Myers, J., "POP3 AUTHentication Command", RFC 1734, December - 1994. - - [R1738] Myers, J., Masinter, L. and M. McCahill, ed's., "Uniform - Resource Locators (URL)", RFC 1738, December 1994. - - [R1750] Eastlake, D., Crocker, S. and J. Schiller, "Randomness - Recommendations for Security", RFC 1750, December 1994. - - [R1777] Yeong, W., Howes, T. and S. Kille, "Lightweight Directory - Access Protocol", RFC 1777, March 1995. - - - - - -Shirey Informational [Page 204] - -RFC 2828 Internet Security Glossary May 2000 - - - [R1808] Fielding, R., "Relative Uniform Resource Locators", RFC - 1808, June 1995. - - [R1824] Danisch, H., "The Exponential Security System TESS: An - Identity-Based Cryptographic Protocol for Authenticated Key- - Exchange (E.I.S.S.-Report 1995/4)", RFC 1824, August 1995. - - [R1828] Metzger, P. and W. Simpson, "IP Authentication using Keyed - MD5", RFC 1828, August 1995. - - [R1829] Karn, P., Metzger, P. and W. Simpson, "The ESP DES-CBC - Transform", RFC 1829, August 1995. - - [R1848] Crocker, S., Freed, N., Galvin, J. and S. Murphy, "MIME - Object Security Services", RFC 1848, October 1995. - - [R1851] Karn, P., Metzger, P. and W. Simpson, "The ESP Triple DES - Transform", RFC 1851, September 1995. - - [R1866] Berners-Lee, T., "Hypertext Markup Language--2.0", RFC 1866, - November 1995. - - [R1885] Conta, A. and S. Deering, "Internet Control Message Protocol - (ICMPv6) for the Internet Protocol Version 6 (IPv6) - Specification", RFC 1885, December 1995. - - [R1928] Leech, M., Ganis, M., Lee, Y., Kuris, R., Koblas, D. and L. - Jones, "SOCKS Protocol Version 5", RFC 1928, March 1996. - - [R1938] Haller, N. and C. Metzion, "A One-Time Password System", RFC - 1938, May 1996. - - [R1939] Myers, J. and M. Rose, "Post Office Protocol - Version 3", - STD 53, RFC 1939, May 1996. - - [R1958] Carpenter, B., ed., "Architectural Principles of the - Internet", RFC 1958, June 1996. - - [R1983] Malkin, G., ed., "Internet Users' Glossary", FYI 18, RFC - 1983, August 1996. - - [R1994] Simpson, W. "PPP Challenge Handshake Authentication Protocol - (CHAP)", RFC 1994, August 1996. - - [R2023] Postel, J. and J. Reynolds, "Instructions to RFC Authors", - RFC 2023, October 1997. - - - - - -Shirey Informational [Page 205] - -RFC 2828 Internet Security Glossary May 2000 - - - [R2026] Bradner, S., "The Internet Standards Process--Revision 3", - BCP 9, RFC 2026, March 1994. - - [R2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail - Extensions (MIME) Part One: Format of Internet Message - Bodies", RFC 2045, November 1996. - - [R2060] Crispin, M., "Internet Message Access Protocol--Version 4 - Revision 1", RFC 2060, December 1996. - - [R2065] Eastlake, D., 3rd, "Domain Name System Security Extensions", - RFC 2065, January 1997. - - [R2078] Linn, J., "Generic Security Service Application Program - Interface, Version 2", RFC 2078, January 1997. - - [R2084] Bossert, G., Cooper, S. and W. Drummond, "Considerations for - Web Transaction Security", RFC 2084, January 1997. - - [R2104] Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed- - Hashing for Message Authentication", RFC 2104, February - 1997. - - [R2119] Bradner, S., "Key Words for Use in RFCs To Indicate - Requirement Levels", BCP 14, RFC 2119, March 1997. - - [R2138] Rigney, C., Rubens, A., Simpson, W. and S. Willens, "Remote - Authentication Dial In User Service (RADIUS)", RFC 2138, - April 1997. - - [R2137] Eastlake, D., "Secure Domain Name System Dynamic Update", - RFC 2137, April 1997. - - [R2179] Gwinn, A., "Network Security For Trade Shows", RFC 2179, - July 1997. - - [R2195] Klensin, J., Catoe, R. and P. Krumviede, "IMAP/POP AUTHorize - Extension for Simple Challenge/Response", RFC 2195, Sepember - 1997. - - [R2196] Fraser, B., "Site Security Handbook", FYI 8, RFC 2196, - Sepember 1997. - - [R2202] Cheng, P. and R. Glenn, "Test Cases for HMAC-MD5 and HMAC- - SHA-1", RFC 2202, Sepember 1997. - - - - - - -Shirey Informational [Page 206] - -RFC 2828 Internet Security Glossary May 2000 - - - [R2222] Myers, J., "Simple Authentication and Security Layer - (SASL)", RFC 2222, October 1997. - - [R2223] Postel, J., "Instructions to RFC Authors", RFC 2223, October - 1997. - - [R2246] Dierks, T. and C. Allen, "The TLS Protocol, Version 1.0", - RFC 2246, January 1999. - - [R2284] Blunk, L. and J. Vollbrecht, "PPP Extensible Authentication - Protocol (EAP)", RFC 2284, March 1998. - - [R2315] Kaliski, B., "PKCS #7: Cryptographic Message Syntax, Version - 1.5", RFC 2315, March 1998. - - [R2323] Ramos, A., "IETF Identification and Security Guidelines", - RFC 2323, 1 April 1998. [Intended for humorous entertainment - ("please laugh loud and hard"); does not contain serious - security information.] - - [R2350] Brownlee, N. and E. Guttman, "Expectations for Computer - Security Incident Response", RFC 2350, June 1998. - - [R2356] Montenegro, C. and V. Gupta, "Sun's SKIP Firewall Traversal - for Mobile IP", RFC 2356, June 1998. - - [R2373] Hinden, R. and S. Deering, "IP Version 6 Addressing - Architecture", RFC 2373, July 2998. - - [R2401] Kent, S. and R. Atkinson, "Security Architecture for the - Internet Protocol", RFC 2401, November 1998. - - [R2402] Kent, S. and R. Atkinson, "IP Authentication Header", RFC - 2402, November 1998. - - [R2403] Madson, C. and R. Glenn, "The Use of HMAC-MD5-96 within ESP - and AH", RFC 2403, November 1998. - - [R2404] Madson, C. and R. Glenn, "The Use of HMAC-SHA-1-96 within - ESP and AH", RFC 2404, November 1998. - - [R2405] Madson, C. and N. Doraswamy, "The ESP DES-CBC Cipher - Algorithm With Explicit IV", RFC 2405, November 1998. - - [R2406] Kent, S. and R. Atkinson, "IP Encapsulating Security Payload - (ESP)", RFC 2406, November 1998. - - - - - -Shirey Informational [Page 207] - -RFC 2828 Internet Security Glossary May 2000 - - - [R2407] Piper, D., "The Internet IP Security Domain of - Interpretation for ISAKMP", RFC 2407, November 1998. - - [R2408] Maughan, D., Schertler, M., Schneider, M. and J. Turner, - "Internet Security Association and Key Management Protocol - (ISAKMP)", RFC 2408, November 1998. - - [R2409] Harkins, D. and D. Carrel, "The Internet Key Exchange - (IKE)", RFC 2409, November 1998. - - [R2410] Glenn, R. and S. Kent, "The NULL Encryption Algorithm and - Its Use With IPsec", RFC 2410, November 1998. - - [R2412] Orman, H., "The OAKLEY Key Determination Protocol", RFC - 2412, November 1998. - - [R2451] Pereira, R. and R. Adams, "The ESP CBC-Mode Cipher - Algorithms", RFC 2451, November 1998. - - [R2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 - (IPv6) Specification", RFC 2460, December 1998. - - [R2504] Guttman, E., Leong, L. and G. Malkin, "Users' Security - Handbook", RFC 2504, February 1999. - - [R2510] Adams, C. and S. Farrell, "Internet X.509 Public Key - Infrastructure Certificate Management Protocols", RFC 2510, - March 1999. - - [R2527] Chokhani, S. and W. Ford, "Internet X.509 Public Key - Infrastructure, Certificate Policy and Certification - Practices Framework", RFC 2527, March 1999. - - [R2536] EastLake, D., "DSA KEYs and SIGs in the Domain Name System - (DNS)", RFC 2536, March 1999. - - [R2570] Case, J., Mundy, R., Partain, D. and B. Stewart, - "Introduction to Version 3 of the Internet-Standard Network - Management Framework", RFC 2570, April 1999. - - [R2574] Blumenthal, U. and B. Wijnen, "User-based Security Model - (USM) for Version 3 of the Simple Network Management - Protocol (SNMPv3)", RFC 2574, April 1999. - - [R2612] Adams, C. and J. Gilchrist, "The CAST-256 Encryption - Algorithm", RFC 2612, June 1999. - - - - - -Shirey Informational [Page 208] - -RFC 2828 Internet Security Glossary May 2000 - - - [R2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, - L., Leach, P. and T. Berners-Lee, "Hypertext Transfer - Protocol-- HTTP/1.1", RFC 2616, June 1999. - - [R2628] Smyslov, V., "Simple Cryptographic Program Interface", RFC - 2628, June 1999. - - [R2630] Housley, R., "Cryptographic Message Syntax", RFC 2630, June - 1999. - - [R2631] Rescorla, E., "Diffie-Hellman Key Agreement Method", RFC - 2631, June 1999. - - [R2633] Ramsdell, B., ed., "S/MIME Version 3 Message Specification", - RFC 2633, June 1999. - - [R2634] Hoffman, P., ed., "Enhanced Security Services for S/MIME", - RFC 2634, June 1999. - - [R2635] Hambridge, S. and A. Lunde, "Don't Spew: A Set of Guidelines - for Mass Unsolicited Mailings and Postings", RFC 2635, June - 1999. - - [Raym] E. S. Raymond, ed., "The On-Line Hacker Jargon File", ver. - 4.0.0, 24 Jul 1996. (Also available as "The New Hacker's - Dictionary", 2nd edition, MIT Press, Sep 1993, ISBN 0-262- - 18154-1. See: http://www.tuxedo.org/jargon/ for the latest - version.) - - [Russ] D. Russell and G. T. Gangemi Sr., Chapter 10 ("TEMPEST") in - "Computer Security Basics", ISBN 0-937175-71-4, 1991. - - [Schn] B. Schneier, "Applied Cryptography", John Wiley & Sons, - Inc., New York, 1994. - - [SDNS3] U.S. Department of Defense, National Security Agency, - "Secure Data Network Systems, Security Protocol 3 (SP3)", - document SDN.301, Revision 1.5, 15 May 1989. - - [SDNS4] ---, ---, "Security Protocol 4 (SP4)", document SDN.401, - Revision 1.2, 12 Jul 1988. - - [SDNS7] ---, ---, "Secure data Network System, Message Security - Protocol (MSP)", document SDN.701, Revision 4.0, 7 Jun 1996, - with Corrections to Message Security Protocol, SDN.701, Rev - 4.0", 96-06-07, 30 Aug, 1996. - - - - - -Shirey Informational [Page 209] - -RFC 2828 Internet Security Glossary May 2000 - - - [SET1] MasterCard and Visa, "SET Secure Electronic Transaction - Specification, Book 1: Business Description", ver. 1.0, 31 - May 1997. - - [SET2] ---, "SET Secure Electronic Transaction Specification, Book - 2: Programmer's Guide", ver. 1.0, 31 May 1997. - - [Stei] J. Steiner, C. Neuman, and J. Schiller, "Kerberos: An - Authentication Service for Open Network Systems" in "Usenix - Conference Proceedings", Feb 1988. - - [X400] International Telecommunications Union--Telecommunication - Standardization Sector (formerly "CCITT"), Recommendation - X.400, "Message Handling Services: Message Handling System - and Service Overview". - - [X500] ---, Recommendation X.500, "Information Technology--Open - Systems Interconnection--The Directory: Overview of - Concepts, Models, and Services". (Equivalent to ISO 9594-1.) - - [X501] ---, Recommendation X.501, "Information Technology--Open - Systems Interconnection--The Directory: Models". - - [X509] ---, Recommendation X.509, "Information Technology--Open - Systems Interconnection--The Directory: Authentication - Framework". (Equivalent to ISO 9594-8.) - - [X519] ---, Recommendation X.519, "Information Technology--Open - Systems Interconnection--The Directory: Protocol - Specifications". - - [X520] ---, Recommendation X.520, "Information Technology--Open - Systems Interconnection--The Directory: Selected Attribute - Types". - - [X680] ---, Recommendation X.680, "Information Technology--Abstract - Syntax Notation One (ASN.1)--Specification of Basic - Notation", 15 Nov 1994. (Equivalent to ISO/IEC 8824-1.) - - [X690] ---, Recommendation X.690, "Information Technology--ASN.1 - Encoding Rules--Specification of Basic Encoding Rules (BER), - Canonical Encoding Rules (CER) and Distinguished Encoding - Rules (DER)", 15 Nov 1994. (Equivalent to ISO/IEC 8825-1.) - - - - - - - - -Shirey Informational [Page 210] - -RFC 2828 Internet Security Glossary May 2000 - - -5. Security Considerations - - This document only defines security terms and recommends how to use - them. It does not describe in detail the vulnerabilities of, threats - to, or mechanisms that protect specific Internet protocols. - -6. Acknowledgments - - Pat Cain, Mike Kong, and Charles Lynn provided meticulous comments on - an early draft. - -7. Author's Address - - Please address all comments to: - - Robert W. Shirey GTE / BBN Technologies - EMail: rshirey@bbn.com Suite 1200, Mail Stop 30/12B2 - Phone: +1 (703) 284-4641 1300 Seventeenth Street North - Fax: +1 (703) 284-2766 Arlington, VA 22209-3801 USA - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Shirey Informational [Page 211] - -RFC 2828 Internet Security Glossary May 2000 - - -8. Full Copyright Statement - - Copyright (C) The Internet Society (2000). All Rights Reserved. - - This document and translations of it may be copied and furnished to - others, and derivative works that comment on or otherwise explain it - or assist in its implementation may be prepared, copied, published - and distributed, in whole or in part, without restriction of any - kind, provided that the above copyright notice and this paragraph are - included on all such copies and derivative works. However, this - document itself may not be modified in any way, such as by removing - the copyright notice or references to the Internet Society or other - Internet organizations, except as needed for the purpose of - developing Internet standards in which case the procedures for - copyrights defined in the Internet Standards process must be - followed, or as required to translate it into languages other than - English. - - The limited permissions granted above are perpetual and will not be - revoked by the Internet Society or its successors or assigns. - - This document and the information contained herein is provided on an - "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING - TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING - BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION - HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF - MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. - -Acknowledgement - - Funding for the RFC Editor function is currently provided by the - Internet Society. - - - - - - - - - - - - - - - - - - - -Shirey Informational [Page 212] -