X-Git-Url: https://git.cryptolib.org/?p=avr-crypto-lib.git;a=blobdiff_plain;f=bcal%2Fbcal-ctr.c;fp=bcal%2Fbcal-ctr.c;h=60df831bd4a9403cb65bb47b32b17e2f2b4d9b72;hp=0000000000000000000000000000000000000000;hb=924aa320bef6f192feecdb67d209c790bd49ea49;hpb=fb4cf7b5c6e5f28d886bd4216f09b8052c7bd013

diff --git a/bcal/bcal-ctr.c b/bcal/bcal-ctr.c
new file mode 100644
index 0000000..60df831
--- /dev/null
+++ b/bcal/bcal-ctr.c
@@ -0,0 +1,95 @@
+/* bcal-ctr.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-basic.h"
+#include "bcal-ctr.h"
+#include "memxor/memxor.h"
+
+static void increment_be(void* block, uint8_t size_B){
+	uint16_t c=1;
+	do{
+		--size_B;
+		c += ((uint8_t*)block)[size_B];
+		((uint8_t*)block)[size_B] = (uint8_t)c;
+		c>>=8;
+	}while(size_B);
+}
+
+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){
+	ctx->desc = (bcdesc_t*)desc;
+	if(inc_func){
+		ctx->inc_func = inc_func;
+	}else{
+		ctx->inc_func = increment_be;
+	}
+	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_ctr_free(bcal_ctr_ctx_t* ctx){
+	free(ctx->in_block);
+	bcal_cipher_free(&(ctx->cctx));
+}
+
+void bcal_ctr_loadIV(const void* iv, bcal_ctr_ctx_t* ctx){
+	if(iv){
+		memcpy(ctx->in_block, iv, ctx->blocksize_B);
+	}
+}
+
+void bcal_ctr_encNext(void* block, bcal_ctr_ctx_t* ctx){
+	uint8_t tmp[ctx->blocksize_B];
+	memcpy(tmp, ctx->in_block, ctx->blocksize_B);
+	bcal_cipher_enc(tmp, &(ctx->cctx));
+	memxor(block, tmp, ctx->blocksize_B);
+	ctx->inc_func(ctx->in_block, ctx->blocksize_B);
+}
+
+void bcal_ctr_decNext(void* block, bcal_ctr_ctx_t* ctx){
+	bcal_ctr_encNext(block, ctx);
+}
+
+void bcal_ctr_encMsg(const void* iv, void* msg, uint32_t msg_len_b, bcal_ctr_ctx_t* ctx){
+	bcal_ctr_loadIV(iv, ctx);
+	uint16_t blocksize_b;
+	blocksize_b = ctx->blocksize_B*8;
+	while(msg_len_b>blocksize_b){
+		bcal_ctr_encNext(msg, ctx);
+		msg_len_b -= blocksize_b;
+		msg = (uint8_t*)msg + ctx->blocksize_B;
+	}
+	uint8_t tmp[ctx->blocksize_B];
+	memcpy(tmp, ctx->in_block, ctx->blocksize_B);
+	bcal_cipher_enc(tmp, &(ctx->cctx));
+	ctx->inc_func(ctx->in_block, ctx->blocksize_B);
+	tmp[msg_len_b/8] = 0xff00>>(msg_len_b&7);
+	memxor(msg, tmp, (msg_len_b+7)/8);
+}
+
+void bcal_ctr_decMsg(const void* iv, void* msg, uint32_t msg_len_b, bcal_ctr_ctx_t* ctx){
+	bcal_ctr_encMsg(iv, msg, msg_len_b, ctx);
+}
+