+/* shabea.c */
+/*
+ This file is part of the Crypto-avr-lib/microcrypt-lib.
+ Copyright (C) 2008 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/>.
+*/
/**
* \file shabea.c
* \author Daniel Otte
* \date 2007-06-07
- * \brief SHABEA - a SHA Based Encrytion Algorithm implementation
+ * \brief SHABEA - a SHA Based Encryption Algorithm implementation
* \par License
* GPL
*
#include "config.h"
#include "uart.h"
#include "debug.h"
-/*
- *
- */
-void memxor(uint8_t * dest, uint8_t * src, uint8_t length){
- while(length--){
- *dest++ ^= *src++;
- }
-}
+#include "memxor.h"
+
/*
- * SHABEA128-16
+ * SHABEA256-n
*/
-#define L ((uint8_t*)block+0)
-#define R ((uint8_t*)block+8)
-void shabea128(void * block, void * key, uint16_t keysize, uint8_t enc, uint8_t rounds){
+
+#define BLOCKSIZE 256
+#define BLOCKSIZEB (BLOCKSIZE/8)
+#define HALFSIZEB (BLOCKSIZEB/2)
+#define HALFSIZE (BLOCKSIZE/2)
+
+#define L ((uint8_t*)block+ 0)
+#define R ((uint8_t*)block+16)
+void shabea256(void * block, void * key, uint16_t keysize_b, uint8_t enc, uint8_t rounds){
int8_t r; /**/
- uint8_t *tb; /**/
+ uint8_t tb[HALFSIZEB+2+(keysize_b+7)/8]; /**/
uint16_t kbs; /* bytes used for the key / temporary block */
sha256_hash_t hash;
r = (enc?0:(rounds-1));
- kbs = keysize/8 + ((keysize&7)?1:0);
- tb = malloc(8+2+kbs);
- memcpy(tb+8+2, key, kbs);
- tb[8+0] = 0;
+ kbs = (keysize_b+7)/8;
+ memcpy(tb+HALFSIZEB+2, key, kbs); /* copy key to temporary block */
+ tb[HALFSIZEB+0] = 0; /* set round counter high value to zero */
for(;r!=(enc?(rounds):-1);enc?r++:r--){ /* enc: 0..(rounds-1) ; !enc: (rounds-1)..0 */
- memcpy(tb, R, 8); /* copy right half into tb */
- tb[8+1] = r;
- sha256(&hash, tb, 64+16+keysize);
+ memcpy(tb, R, HALFSIZEB); /* copy right half into tb */
+ tb[HALFSIZEB+1] = r;
+ sha256(&hash, tb, HALFSIZE+16+keysize_b);
if(!(r==(enc?(rounds-1):0))){
/* swap */
- memxor(hash, L, 8);
- memcpy(L, R, 8);
- memcpy(R, hash, 8);
+ memxor(hash, L, HALFSIZEB);
+ memcpy(L, R, HALFSIZEB);
+ memcpy(R, hash, HALFSIZEB);
} else {
/* no swap */
- memxor(L, hash, 8);
+ memxor(L, hash, HALFSIZEB);
}
}
- free(tb);
}