96 lines
2.7 KiB
C
96 lines
2.7 KiB
C
/* bcal-ctr.c */
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/*
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This file is part of the ARM-Crypto-Lib.
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Copyright (C) 2006-2010 Daniel Otte (daniel.otte@rub.de)
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdint.h>
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#include <string.h>
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#include "bcal-basic.h"
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#include "bcal-ctr.h"
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#include "memxor.h"
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static void increment_be(void* block, uint8_t size_B){
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uint16_t c=1;
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do{
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--size_B;
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c += ((uint8_t*)block)[size_B];
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((uint8_t*)block)[size_B] = (uint8_t)c;
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c>>=8;
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}while(size_B);
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}
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uint8_t bcal_ctr_init(const bcdesc_t* desc, const void* key, uint16_t keysize_b, inc_fp_t inc_func, bcal_ctr_ctx_t* ctx){
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ctx->desc = (bcdesc_t*)desc;
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if(inc_func){
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ctx->inc_func = inc_func;
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}else{
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ctx->inc_func = increment_be;
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}
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ctx->blocksize_B = (bcal_cipher_getBlocksize_b(desc)+7)/8;
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ctx->in_block=malloc(ctx->blocksize_B);
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if(ctx->in_block==NULL){
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return 0x11;
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}
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return bcal_cipher_init(desc, key, keysize_b, &(ctx->cctx));
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}
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void bcal_ctr_free(bcal_ctr_ctx_t* ctx){
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free(ctx->in_block);
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bcal_cipher_free(&(ctx->cctx));
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}
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void bcal_ctr_loadIV(const void* iv, bcal_ctr_ctx_t* ctx){
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if(iv){
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memcpy(ctx->in_block, iv, ctx->blocksize_B);
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}
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}
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void bcal_ctr_encNext(void* block, bcal_ctr_ctx_t* ctx){
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uint8_t tmp[ctx->blocksize_B];
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memcpy(tmp, ctx->in_block, ctx->blocksize_B);
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bcal_cipher_enc(tmp, &(ctx->cctx));
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memxor(block, tmp, ctx->blocksize_B);
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ctx->inc_func(ctx->in_block, ctx->blocksize_B);
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}
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void bcal_ctr_decNext(void* block, bcal_ctr_ctx_t* ctx){
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bcal_ctr_encNext(block, ctx);
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}
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void bcal_ctr_encMsg(const void* iv, void* msg, uint32_t msg_len_b, bcal_ctr_ctx_t* ctx){
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bcal_ctr_loadIV(iv, ctx);
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uint16_t blocksize_b;
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blocksize_b = ctx->blocksize_B*8;
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while(msg_len_b>blocksize_b){
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bcal_ctr_encNext(msg, ctx);
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msg_len_b -= blocksize_b;
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msg = (uint8_t*)msg + ctx->blocksize_B;
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}
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uint8_t tmp[ctx->blocksize_B];
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memcpy(tmp, ctx->in_block, ctx->blocksize_B);
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bcal_cipher_enc(tmp, &(ctx->cctx));
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ctx->inc_func(ctx->in_block, ctx->blocksize_B);
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tmp[msg_len_b/8] = 0xff00>>(msg_len_b&7);
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memxor(msg, tmp, (msg_len_b+7)/8);
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}
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void bcal_ctr_decMsg(const void* iv, void* msg, uint32_t msg_len_b, bcal_ctr_ctx_t* ctx){
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bcal_ctr_encMsg(iv, msg, msg_len_b, ctx);
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}
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