arm-crypto-lib/bcal/bcal-ofb.c

77 lines
2.3 KiB
C

/* bcal-ofb.c */
/*
This file is part of the ARM-Crypto-Lib.
Copyright (C) 2006-2010 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-ofb.h"
#include "bcal-basic.h"
#include "memxor.h"
uint8_t bcal_ofb_init(const bcdesc_t* desc, const void* key, uint16_t keysize_b, bcal_ofb_ctx_t* ctx){
ctx->desc = (bcdesc_t*)desc;
ctx->blocksize_B = (bcal_cipher_getBlocksize_b(desc)+7)/8;
ctx->in_block=malloc(ctx->blocksize_B);
if(ctx->in_block==NULL){
return 0x11;
}
return bcal_cipher_init(desc, key, keysize_b, &(ctx->cctx));
}
void bcal_ofb_free(bcal_ofb_ctx_t* ctx){
free(ctx->in_block);
bcal_cipher_free(&(ctx->cctx));
}
void bcal_ofb_loadIV(const void* iv, bcal_ofb_ctx_t* ctx){
if(iv){
memcpy(ctx->in_block, iv, ctx->blocksize_B);
}
}
void bcal_ofb_encNext(void* block, bcal_ofb_ctx_t* ctx){
bcal_cipher_enc(ctx->in_block , &(ctx->cctx));
memxor(block, ctx->in_block, ctx->blocksize_B);
}
void bcal_ofb_decNext(void* block, bcal_ofb_ctx_t* ctx){
bcal_cipher_enc(ctx->in_block , &(ctx->cctx));
memxor(block, ctx->in_block, ctx->blocksize_B);
}
void bcal_ofb_encMsg(const void* iv, void* msg, uint32_t msg_len_b, bcal_ofb_ctx_t* ctx){
uint16_t block_len_b;
block_len_b = ctx->blocksize_B*8;
bcal_ofb_loadIV(iv, ctx);
while(msg_len_b>block_len_b){
bcal_ofb_encNext(msg, ctx);
msg_len_b -= block_len_b;
msg = (uint8_t*)msg + ctx->blocksize_B;
}
bcal_cipher_enc(ctx->in_block, &(ctx->cctx));
ctx->in_block[msg_len_b/8] = 0xff00>>(msg_len_b&7);
memxor(msg, ctx->in_block, (msg_len_b+7)/8);
}
void bcal_ofb_decMsg(const void* iv, void* msg, uint32_t msg_len_b, bcal_ofb_ctx_t* ctx){
bcal_ofb_encMsg(iv, msg, msg_len_b, ctx);
}