95 lines
2.7 KiB
C
95 lines
2.7 KiB
C
/* bcal-cbc.c */
|
|
/*
|
|
This file is part of the AVR-Crypto-Lib.
|
|
Copyright (C) 2010 Daniel Otte (daniel.otte@rub.de)
|
|
|
|
This program is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation, either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
#include "bcal-cbc.h"
|
|
#include "bcal-basic.h"
|
|
#include "memxor.h"
|
|
|
|
uint8_t bcal_cbc_init(const bcdesc_t *desc, const void *key, uint16_t keysize_b,
|
|
bcal_cbc_ctx_t *ctx)
|
|
{
|
|
ctx->desc = (bcdesc_t*) desc;
|
|
ctx->blocksize_B = (bcal_cipher_getBlocksize_b(desc) + 7) / 8;
|
|
ctx->prev_block = malloc(ctx->blocksize_B);
|
|
|
|
if (ctx->prev_block == NULL) {
|
|
return 0x11;
|
|
}
|
|
return bcal_cipher_init(desc, key, keysize_b, &(ctx->cctx));
|
|
}
|
|
|
|
void bcal_cbc_free(bcal_cbc_ctx_t *ctx)
|
|
{
|
|
bcal_cipher_free(&(ctx->cctx));
|
|
free(ctx->prev_block);
|
|
}
|
|
|
|
void bcal_cbc_loadIV(const void *iv, bcal_cbc_ctx_t *ctx)
|
|
{
|
|
if (iv) {
|
|
memcpy(ctx->prev_block, iv, ctx->blocksize_B);
|
|
}
|
|
}
|
|
|
|
void bcal_cbc_encNext(void *block, bcal_cbc_ctx_t *ctx)
|
|
{
|
|
memxor(block, ctx->prev_block, ctx->blocksize_B);
|
|
bcal_cipher_enc(block, &(ctx->cctx));
|
|
memcpy(ctx->prev_block, block, ctx->blocksize_B);
|
|
}
|
|
|
|
void bcal_cbc_decNext(void *block, bcal_cbc_ctx_t *ctx)
|
|
{
|
|
uint8_t tmp[ctx->blocksize_B];
|
|
memcpy(tmp, block, ctx->blocksize_B);
|
|
bcal_cipher_dec(block, &(ctx->cctx));
|
|
memxor(block, ctx->prev_block, ctx->blocksize_B);
|
|
memcpy(ctx->prev_block, tmp, ctx->blocksize_B);
|
|
}
|
|
void bcal_cbc_decRand(void *block, const void *prev_block, bcal_cbc_ctx_t *ctx)
|
|
{
|
|
bcal_cipher_dec(block, &(ctx->cctx));
|
|
memxor(block, prev_block, ctx->blocksize_B);
|
|
}
|
|
|
|
void bcal_cbc_encMsg(const void *iv, void *msg, uint16_t msg_blocks,
|
|
bcal_cbc_ctx_t *ctx)
|
|
{
|
|
bcal_cbc_loadIV(iv, ctx);
|
|
while (msg_blocks--) {
|
|
bcal_cbc_encNext(msg, ctx);
|
|
msg = (uint8_t*) msg + ctx->blocksize_B;
|
|
}
|
|
}
|
|
|
|
void bcal_cbc_decMsg(const void *iv, void *msg, uint16_t msg_blocks,
|
|
bcal_cbc_ctx_t *ctx)
|
|
{
|
|
msg = (uint8_t*) msg + (msg_blocks - 1) * ctx->blocksize_B;
|
|
while (msg_blocks > 1) {
|
|
bcal_cbc_decRand(msg, (uint8_t*) msg - ctx->blocksize_B, ctx);
|
|
msg_blocks -= 1;
|
|
msg = (uint8_t*) msg - ctx->blocksize_B;
|
|
}
|
|
bcal_cbc_decRand(msg, iv, ctx);
|
|
}
|
|
|