2 * \file rsa_internal.h
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4 * \brief Context-independent RSA helper functions
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6 * This module declares some RSA-related helper functions useful when
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7 * implementing the RSA interface. These functions are provided in a separate
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8 * compilation unit in order to make it easy for designers of alternative RSA
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9 * implementations to use them in their own code, as it is conceived that the
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10 * functionality they provide will be necessary for most complete
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13 * End-users of Mbed TLS who are not providing their own alternative RSA
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14 * implementations should not use these functions directly, and should instead
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15 * use only the functions declared in rsa.h.
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17 * The interface provided by this module will be maintained through LTS (Long
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18 * Term Support) branches of Mbed TLS, but may otherwise be subject to change,
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19 * and must be considered an internal interface of the library.
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21 * There are two classes of helper functions:
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23 * (1) Parameter-generating helpers. These are:
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24 * - mbedtls_rsa_deduce_primes
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25 * - mbedtls_rsa_deduce_private_exponent
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26 * - mbedtls_rsa_deduce_crt
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27 * Each of these functions takes a set of core RSA parameters and
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28 * generates some other, or CRT related parameters.
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30 * (2) Parameter-checking helpers. These are:
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31 * - mbedtls_rsa_validate_params
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32 * - mbedtls_rsa_validate_crt
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33 * They take a set of core or CRT related RSA parameters and check their
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38 * Copyright (C) 2006-2017, ARM Limited, All Rights Reserved
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39 * SPDX-License-Identifier: Apache-2.0
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41 * Licensed under the Apache License, Version 2.0 (the "License"); you may
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42 * not use this file except in compliance with the License.
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43 * You may obtain a copy of the License at
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45 * http://www.apache.org/licenses/LICENSE-2.0
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47 * Unless required by applicable law or agreed to in writing, software
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48 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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49 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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50 * See the License for the specific language governing permissions and
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51 * limitations under the License.
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53 * This file is part of mbed TLS (https://tls.mbed.org)
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57 #ifndef MBEDTLS_RSA_INTERNAL_H
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58 #define MBEDTLS_RSA_INTERNAL_H
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60 #if !defined(MBEDTLS_CONFIG_FILE)
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63 #include MBEDTLS_CONFIG_FILE
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74 * \brief Compute RSA prime moduli P, Q from public modulus N=PQ
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75 * and a pair of private and public key.
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77 * \note This is a 'static' helper function not operating on
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78 * an RSA context. Alternative implementations need not
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81 * \param N RSA modulus N = PQ, with P, Q to be found
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82 * \param E RSA public exponent
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83 * \param D RSA private exponent
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84 * \param P Pointer to MPI holding first prime factor of N on success
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85 * \param Q Pointer to MPI holding second prime factor of N on success
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88 * - 0 if successful. In this case, P and Q constitute a
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89 * factorization of N.
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90 * - A non-zero error code otherwise.
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92 * \note It is neither checked that P, Q are prime nor that
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93 * D, E are modular inverses wrt. P-1 and Q-1. For that,
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94 * use the helper function \c mbedtls_rsa_validate_params.
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97 int mbedtls_rsa_deduce_primes( mbedtls_mpi const *N, mbedtls_mpi const *E,
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98 mbedtls_mpi const *D,
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99 mbedtls_mpi *P, mbedtls_mpi *Q );
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102 * \brief Compute RSA private exponent from
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103 * prime moduli and public key.
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105 * \note This is a 'static' helper function not operating on
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106 * an RSA context. Alternative implementations need not
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109 * \param P First prime factor of RSA modulus
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110 * \param Q Second prime factor of RSA modulus
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111 * \param E RSA public exponent
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112 * \param D Pointer to MPI holding the private exponent on success.
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115 * - 0 if successful. In this case, D is set to a simultaneous
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116 * modular inverse of E modulo both P-1 and Q-1.
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117 * - A non-zero error code otherwise.
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119 * \note This function does not check whether P and Q are primes.
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122 int mbedtls_rsa_deduce_private_exponent( mbedtls_mpi const *P,
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123 mbedtls_mpi const *Q,
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124 mbedtls_mpi const *E,
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129 * \brief Generate RSA-CRT parameters
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131 * \note This is a 'static' helper function not operating on
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132 * an RSA context. Alternative implementations need not
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135 * \param P First prime factor of N
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136 * \param Q Second prime factor of N
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137 * \param D RSA private exponent
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138 * \param DP Output variable for D modulo P-1
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139 * \param DQ Output variable for D modulo Q-1
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140 * \param QP Output variable for the modular inverse of Q modulo P.
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142 * \return 0 on success, non-zero error code otherwise.
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144 * \note This function does not check whether P, Q are
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145 * prime and whether D is a valid private exponent.
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148 int mbedtls_rsa_deduce_crt( const mbedtls_mpi *P, const mbedtls_mpi *Q,
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149 const mbedtls_mpi *D, mbedtls_mpi *DP,
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150 mbedtls_mpi *DQ, mbedtls_mpi *QP );
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154 * \brief Check validity of core RSA parameters
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156 * \note This is a 'static' helper function not operating on
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157 * an RSA context. Alternative implementations need not
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160 * \param N RSA modulus N = PQ
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161 * \param P First prime factor of N
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162 * \param Q Second prime factor of N
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163 * \param D RSA private exponent
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164 * \param E RSA public exponent
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165 * \param f_rng PRNG to be used for primality check, or NULL
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166 * \param p_rng PRNG context for f_rng, or NULL
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169 * - 0 if the following conditions are satisfied
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170 * if all relevant parameters are provided:
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171 * - P prime if f_rng != NULL (%)
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172 * - Q prime if f_rng != NULL (%)
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175 * - D and E are modular inverses modulo P-1 and Q-1
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176 * (%) This is only done if MBEDTLS_GENPRIME is defined.
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177 * - A non-zero error code otherwise.
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179 * \note The function can be used with a restricted set of arguments
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180 * to perform specific checks only. E.g., calling it with
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181 * (-,P,-,-,-) and a PRNG amounts to a primality check for P.
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183 int mbedtls_rsa_validate_params( const mbedtls_mpi *N, const mbedtls_mpi *P,
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184 const mbedtls_mpi *Q, const mbedtls_mpi *D,
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185 const mbedtls_mpi *E,
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186 int (*f_rng)(void *, unsigned char *, size_t),
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190 * \brief Check validity of RSA CRT parameters
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192 * \note This is a 'static' helper function not operating on
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193 * an RSA context. Alternative implementations need not
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196 * \param P First prime factor of RSA modulus
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197 * \param Q Second prime factor of RSA modulus
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198 * \param D RSA private exponent
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199 * \param DP MPI to check for D modulo P-1
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200 * \param DQ MPI to check for D modulo P-1
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201 * \param QP MPI to check for the modular inverse of Q modulo P.
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204 * - 0 if the following conditions are satisfied:
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205 * - D = DP mod P-1 if P, D, DP != NULL
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206 * - Q = DQ mod P-1 if P, D, DQ != NULL
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207 * - QP = Q^-1 mod P if P, Q, QP != NULL
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208 * - \c MBEDTLS_ERR_RSA_KEY_CHECK_FAILED if check failed,
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209 * potentially including \c MBEDTLS_ERR_MPI_XXX if some
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210 * MPI calculations failed.
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211 * - \c MBEDTLS_ERR_RSA_BAD_INPUT_DATA if insufficient
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212 * data was provided to check DP, DQ or QP.
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214 * \note The function can be used with a restricted set of arguments
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215 * to perform specific checks only. E.g., calling it with the
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216 * parameters (P, -, D, DP, -, -) will check DP = D mod P-1.
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218 int mbedtls_rsa_validate_crt( const mbedtls_mpi *P, const mbedtls_mpi *Q,
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219 const mbedtls_mpi *D, const mbedtls_mpi *DP,
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220 const mbedtls_mpi *DQ, const mbedtls_mpi *QP );
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226 #endif /* rsa_internal.h */
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