Add rivest cipher 4 (rc4) implementation

Add an implementation of RC4. This will be used by Rockchip booting but may
be useful in other situations.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/include/rc4.h b/include/rc4.h
new file mode 100644 (file)
index 0000000..ea409c2
--- /dev/null
+++ b/include/rc4.h
@@ -0,0 +1,21 @@
+/*
+ * (C) Copyright 2015 Google, Inc
+ *
+ * (C) Copyright 2008-2014 Rockchip Electronics
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#ifndef __RC4_H
+#define __RC4_H
+
+/**
+ * rc4_encode() - encode a buf with the RC4 cipher
+ *
+ * @buf:       Buffer to encode (it is overwrite in the process
+ * @len:       Length of buffer in bytes
+ * @key:       16-byte key to use
+ */
+void rc4_encode(unsigned char *buf, unsigned int len, unsigned char key[16]);
+
+#endif

diff --git a/lib/Makefile b/lib/Makefile
index 1139f9b75513d80fd03eba5b86370cc90fd2a228..fd106b91c80f0335fbdeb66a8bb4d53fb07c0900 100644 (file)
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_MD5) += md5.o
 obj-y += net_utils.o
 obj-$(CONFIG_PHYSMEM) += physmem.o
 obj-y += qsort.o
+obj-y += rc4.o
 obj-$(CONFIG_SHA1) += sha1.o
 obj-$(CONFIG_SUPPORT_EMMC_RPMB) += sha256.o
 obj-$(CONFIG_SHA256) += sha256.o

diff --git a/lib/rc4.c b/lib/rc4.c
new file mode 100644 (file)
index 0000000..89d15f3
--- /dev/null
+++ b/lib/rc4.c
@@ -0,0 +1,49 @@
+/*
+ * (C) Copyright 2015 Google, Inc
+ *
+ * (C) Copyright 2008-2014 Rockchip Electronics
+ *
+ * Rivest Cipher 4 (RC4) implementation
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#ifndef USE_HOSTCC
+#include <common.h>
+#endif
+#include <rc4.h>
+
+void rc4_encode(unsigned char *buf, unsigned int len, unsigned char key[16])
+{
+       unsigned char s[256], k[256], temp;
+       unsigned short i, j, t;
+       int ptr;
+
+       j = 0;
+       for (i = 0; i < 256; i++) {
+               s[i] = (unsigned char)i;
+               j &= 0x0f;
+               k[i] = key[j];
+               j++;
+       }
+
+       j = 0;
+       for (i = 0; i < 256; i++) {
+               j = (j + s[i] + k[i]) % 256;
+               temp = s[i];
+               s[i] = s[j];
+               s[j] = temp;
+       }
+
+       i = 0;
+       j = 0;
+       for (ptr = 0; ptr < len; ptr++) {
+               i = (i + 1) % 256;
+               j = (j + s[i]) % 256;
+               temp = s[i];
+               s[i] = s[j];
+               s[j] = temp;
+               t = (s[i] + (s[j] % 256)) % 256;
+               buf[ptr] = buf[ptr] ^ s[t];
+       }
+}