168 lines
4.8 KiB
C
168 lines
4.8 KiB
C
/**
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* @file aesCBC.c
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* @version $Format:%h%d$
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*
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* AES CBC block cipher implementation.
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*/
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/*
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* Copyright (c) 2013-2017 Rambus Inc.
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* Copyright (c) PeerSec Networks, 2002-2011
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* All Rights Reserved
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*
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* The latest version of this code is available at http://www.matrixssl.org
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*
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* This software is open source; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This General Public License does NOT permit incorporating this software
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* into proprietary programs. If you are unable to comply with the GPL, a
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* commercial license for this software may be purchased from Rambus at
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* http://www.rambus.com/
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*
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* This program is distributed in WITHOUT ANY WARRANTY; without even the
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* implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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* http://www.gnu.org/copyleft/gpl.html
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*/
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/******************************************************************************/
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#include "../cryptoImpl.h"
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#ifdef USE_MATRIX_AES_CBC
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/******************************************************************************/
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void psAesClearCBC(psAesCbc_t *ctx)
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{
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/* Only need to clear block if it's implemented externally, Matrix block
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is part of CipherContext and will be cleared below */
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# ifndef USE_MATRIX_AES_BLOCK
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psAesClearBlockKey(&ctx->key);
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# endif
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memset_s(ctx, sizeof(psAesCbc_t), 0x0, sizeof(psAesCbc_t));
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}
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/******************************************************************************/
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/*
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Software implementation of AES CBC APIs
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*/
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int32_t psAesInitCBC(psAesCbc_t *ctx,
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const unsigned char IV[AES_IVLEN],
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const unsigned char key[AES_MAXKEYLEN], uint8_t keylen,
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uint32_t flags)
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{
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int32_t x, err;
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# ifdef CRYPTO_ASSERT
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if (IV == NULL || key == NULL || ctx == NULL ||
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!(flags & (PS_AES_ENCRYPT | PS_AES_DECRYPT)))
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{
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psTraceCrypto("psAesInitCBC arg fail\n");
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return PS_ARG_FAIL;
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}
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# endif
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if ((err = psAesInitBlockKey(&ctx->key, key, keylen, flags)) != PS_SUCCESS)
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{
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return err;
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}
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for (x = 0; x < AES_BLOCKLEN; x++)
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{
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ctx->IV[x] = IV[x];
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}
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return PS_SUCCESS;
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}
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/******************************************************************************/
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void psAesEncryptCBC(psAesCbc_t *ctx,
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const unsigned char *pt, unsigned char *ct,
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uint32_t len)
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{
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uint32_t i, j;
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unsigned char tmp[AES_BLOCKLEN];
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# ifdef CRYPTO_ASSERT
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if (pt == NULL || ct == NULL || ctx == NULL || (len & 0x7) != 0 ||
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ctx->key.type != PS_AES_ENCRYPT)
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{
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psTraceCrypto("Bad parameters to psAesEncryptCBC\n");
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return;
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}
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# endif
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for (i = 0; i < len; i += AES_BLOCKLEN)
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{
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/* xor IV against plaintext */
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for (j = 0; j < AES_BLOCKLEN; j++)
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{
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tmp[j] = pt[j] ^ ctx->IV[j];
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}
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psAesEncryptBlock(&ctx->key, tmp, ct);
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/* store IV [ciphertext] for a future block */
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for (j = 0; j < AES_BLOCKLEN; j++)
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{
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ctx->IV[j] = ct[j];
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}
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ct += AES_BLOCKLEN;
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pt += AES_BLOCKLEN;
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}
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memset_s(tmp, sizeof(tmp), 0x0, sizeof(tmp));
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}
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/******************************************************************************/
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void psAesDecryptCBC(psAesCbc_t *ctx,
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const unsigned char *ct, unsigned char *pt,
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uint32_t len)
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{
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uint32_t i, j;
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unsigned char tmp[AES_BLOCKLEN], tmp2[AES_BLOCKLEN];
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# ifdef CRYPTO_ASSERT
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if (pt == NULL || ct == NULL || ctx == NULL || (len & 0x7) != 0 ||
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ctx->key.type != PS_AES_DECRYPT)
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{
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psTraceCrypto("Bad parameters to psAesDecryptCBC\n");
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return;
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}
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# endif
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for (i = 0; i < len; i += AES_BLOCKLEN)
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{
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psAesDecryptBlock(&ctx->key, ct, tmp);
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/* xor IV against the plaintext of the previous step */
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for (j = 0; j < AES_BLOCKLEN; j++)
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{
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/* copy CT in case ct == pt */
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tmp2[j] = ct[j];
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/* actually decrypt the byte */
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pt[j] = tmp[j] ^ ctx->IV[j];
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}
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/* replace IV with this current ciphertext */
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for (j = 0; j < AES_BLOCKLEN; j++)
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{
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ctx->IV[j] = tmp2[j];
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}
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ct += AES_BLOCKLEN;
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pt += AES_BLOCKLEN;
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}
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memset_s(tmp, sizeof(tmp), 0x0, sizeof(tmp));
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memset_s(tmp2, sizeof(tmp2), 0x0, sizeof(tmp2));
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}
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#endif /* USE_MATRIX_AES_CBC */
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/******************************************************************************/
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