129 lines
3.6 KiB
C
129 lines
3.6 KiB
C
/* bcal-cfb_bit.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-cfb_bit.h"
|
|
#include "bcal-basic.h"
|
|
|
|
static uint8_t read_bit(void *block, uint32_t index){
|
|
uint8_t r;
|
|
r=((uint8_t*)block)[index/8];
|
|
r=(r&(0x80>>(index&7)))?0xff:0x00;
|
|
return r;
|
|
}
|
|
|
|
static void write_bit(void *block, uint32_t index, uint8_t value){
|
|
if(value){
|
|
/* set bit */
|
|
((uint8_t*)block)[index/8] |= 0x80>>(index&7);
|
|
}else{
|
|
/* clear bit */
|
|
((uint8_t*)block)[index/8] &= ~(0x80>>(index&7));
|
|
}
|
|
}
|
|
|
|
uint8_t bcal_cfb_b_init(const bcdesc_t *desc, const void *key, uint16_t keysize_b, uint16_t size_b, bcal_cfb_b_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;
|
|
}
|
|
if(size_b>bcal_cipher_getBlocksize_b(desc)){
|
|
return 0x12;
|
|
}
|
|
ctx->size_b = size_b;
|
|
return bcal_cipher_init(desc, key, keysize_b, &(ctx->cctx));
|
|
}
|
|
|
|
void bcal_cfb_b_free(bcal_cfb_b_ctx_t *ctx){
|
|
free(ctx->in_block);
|
|
bcal_cipher_free(&(ctx->cctx));
|
|
}
|
|
|
|
void bcal_cfb_b_loadIV(const void *iv, bcal_cfb_b_ctx_t *ctx){
|
|
if(iv){
|
|
memcpy(ctx->in_block, iv, ctx->blocksize_B);
|
|
}
|
|
}
|
|
|
|
void bcal_cfb_b_encNext(void *block, uint8_t offset, bcal_cfb_b_ctx_t *ctx){
|
|
uint8_t tmp[ctx->blocksize_B];
|
|
offset &= 7;
|
|
memcpy(tmp, ctx->in_block, ctx->blocksize_B);
|
|
bcal_cipher_enc(tmp, &(ctx->cctx));
|
|
uint16_t i,j;
|
|
uint8_t a;
|
|
for(i=0; i<ctx->blocksize_B*8-ctx->size_b; ++i){
|
|
a = read_bit(ctx->in_block, i+ctx->size_b);
|
|
write_bit(ctx->in_block, i, a);
|
|
}
|
|
for(j=offset,i=0; i<ctx->size_b; ++i, ++j){
|
|
a = read_bit(tmp, i) ^ read_bit(block, j);
|
|
write_bit(ctx->in_block, ctx->blocksize_B*8-ctx->size_b+i, a);
|
|
write_bit(block, j, a);
|
|
}
|
|
}
|
|
|
|
void bcal_cfb_b_decNext(void *block, uint8_t offset, bcal_cfb_b_ctx_t *ctx){
|
|
uint8_t tmp[ctx->blocksize_B];
|
|
offset &= 7;
|
|
memcpy(tmp, ctx->in_block, ctx->blocksize_B);
|
|
bcal_cipher_enc(tmp, &(ctx->cctx));
|
|
uint16_t i,j;
|
|
uint8_t a,b;
|
|
for(i=0; i<ctx->blocksize_B*8-ctx->size_b; ++i){
|
|
a = read_bit(ctx->in_block, i+ctx->size_b);
|
|
write_bit(ctx->in_block, i, a);
|
|
}
|
|
for(j=offset,i=0; i<ctx->size_b; ++i, ++j){
|
|
a = read_bit(tmp, i);
|
|
b = read_bit(block, j);
|
|
a ^= b;
|
|
write_bit(ctx->in_block, ctx->blocksize_B*8-ctx->size_b+i, b);
|
|
write_bit(block, j, a);
|
|
}
|
|
}
|
|
|
|
void bcal_cfb_b_encMsg(const void *iv, void *msg, uint8_t offset, uint32_t msg_blocks, bcal_cfb_b_ctx_t *ctx){
|
|
bcal_cfb_b_loadIV(iv, ctx);
|
|
uint32_t addr;
|
|
addr = ((uint16_t)msg)*8+offset;
|
|
while(msg_blocks--){
|
|
msg = (void*)((uint16_t)(addr/8));
|
|
offset = addr&7;
|
|
bcal_cfb_b_encNext(msg, offset, ctx);
|
|
addr += ctx->size_b;
|
|
}
|
|
}
|
|
|
|
void bcal_cfb_b_decMsg(const void *iv, void *msg, uint8_t offset, uint32_t msg_blocks, bcal_cfb_b_ctx_t *ctx){
|
|
bcal_cfb_b_loadIV(iv, ctx);
|
|
uint32_t addr;
|
|
addr = ((uint16_t)msg)*8+offset;
|
|
while(msg_blocks--){
|
|
msg = (void*)((uint16_t)(addr/8));
|
|
offset = addr&7;
|
|
bcal_cfb_b_decNext(msg, offset, ctx);
|
|
addr += ctx->size_b;
|
|
}
|
|
}
|