3 This file is part of the AVR-Crypto-Lib.
4 Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
23 #include "bcal-basic.h"
26 uint8_t bcal_cbc_init(const bcdesc_t *desc, const void *key, uint16_t keysize_b,
29 ctx->desc = (bcdesc_t*) desc;
30 ctx->blocksize_B = (bcal_cipher_getBlocksize_b(desc) + 7) / 8;
31 ctx->prev_block = malloc(ctx->blocksize_B);
33 if (ctx->prev_block == NULL) {
36 return bcal_cipher_init(desc, key, keysize_b, &(ctx->cctx));
39 void bcal_cbc_free(bcal_cbc_ctx_t *ctx)
41 bcal_cipher_free(&(ctx->cctx));
42 free(ctx->prev_block);
45 void bcal_cbc_loadIV(const void *iv, bcal_cbc_ctx_t *ctx)
48 memcpy(ctx->prev_block, iv, ctx->blocksize_B);
52 void bcal_cbc_encNext(void *block, bcal_cbc_ctx_t *ctx)
54 memxor(block, ctx->prev_block, ctx->blocksize_B);
55 bcal_cipher_enc(block, &(ctx->cctx));
56 memcpy(ctx->prev_block, block, ctx->blocksize_B);
59 void bcal_cbc_decNext(void *block, bcal_cbc_ctx_t *ctx)
61 uint8_t tmp[ctx->blocksize_B];
62 memcpy(tmp, block, ctx->blocksize_B);
63 bcal_cipher_dec(block, &(ctx->cctx));
64 memxor(block, ctx->prev_block, ctx->blocksize_B);
65 memcpy(ctx->prev_block, tmp, ctx->blocksize_B);
67 void bcal_cbc_decRand(void *block, const void *prev_block, bcal_cbc_ctx_t *ctx)
69 bcal_cipher_dec(block, &(ctx->cctx));
70 memxor(block, prev_block, ctx->blocksize_B);
73 void bcal_cbc_encMsg(const void *iv, void *msg, uint16_t msg_blocks,
76 bcal_cbc_loadIV(iv, ctx);
77 while (msg_blocks--) {
78 bcal_cbc_encNext(msg, ctx);
79 msg = (uint8_t*) msg + ctx->blocksize_B;
83 void bcal_cbc_decMsg(const void *iv, void *msg, uint16_t msg_blocks,
86 msg = (uint8_t*) msg + (msg_blocks - 1) * ctx->blocksize_B;
87 while (msg_blocks > 1) {
88 bcal_cbc_decRand(msg, (uint8_t*) msg - ctx->blocksize_B, ctx);
90 msg = (uint8_t*) msg - ctx->blocksize_B;
92 bcal_cbc_decRand(msg, iv, ctx);