3 This file is part of the AVR-Crypto-Lib.
4 Copyright (C) 2010 Daniel Otte (daniel.otte@rub.de)
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_ofb_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->in_block = malloc(ctx->blocksize_B);
32 if (ctx->in_block == NULL) {
35 return bcal_cipher_init(desc, key, keysize_b, &(ctx->cctx));
38 void bcal_ofb_free(bcal_ofb_ctx_t *ctx)
41 bcal_cipher_free(&(ctx->cctx));
44 void bcal_ofb_loadIV(const void *iv, bcal_ofb_ctx_t *ctx)
47 memcpy(ctx->in_block, iv, ctx->blocksize_B);
51 void bcal_ofb_encNext(void *block, bcal_ofb_ctx_t *ctx)
53 bcal_cipher_enc(ctx->in_block, &(ctx->cctx));
54 memxor(block, ctx->in_block, ctx->blocksize_B);
57 void bcal_ofb_decNext(void *block, bcal_ofb_ctx_t *ctx)
59 bcal_cipher_enc(ctx->in_block, &(ctx->cctx));
60 memxor(block, ctx->in_block, ctx->blocksize_B);
63 void bcal_ofb_encMsg(const void *iv, void *msg, uint32_t msg_len_b,
67 block_len_b = ctx->blocksize_B * 8;
68 bcal_ofb_loadIV(iv, ctx);
69 while (msg_len_b > block_len_b) {
70 bcal_ofb_encNext(msg, ctx);
71 msg_len_b -= block_len_b;
72 msg = (uint8_t*) msg + ctx->blocksize_B;
74 bcal_cipher_enc(ctx->in_block, &(ctx->cctx));
75 ctx->in_block[msg_len_b / 8] = 0xff00 >> (msg_len_b & 7);
76 memxor(msg, ctx->in_block, (msg_len_b + 7) / 8);
79 void bcal_ofb_decMsg(const void *iv, void *msg, uint32_t msg_len_b,
82 bcal_ofb_encMsg(iv, msg, msg_len_b, ctx);