X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=shabea.c;h=b59e138e23ca13f2569def3ac5f029649d196b3b;hb=8f855d283a31a468ea014774c4723a8b77b81644;hp=7acb4d3f9b9be78a2b2d80a5657e3208a2cba3e2;hpb=2b3e134485c42a28f4d8d981c8cb62dc27e71aa5;p=avr-crypto-lib.git

diff --git a/shabea.c b/shabea.c
index 7acb4d3..b59e138 100644
--- a/shabea.c
+++ b/shabea.c
@@ -1,3 +1,24 @@
+/* shabea.c */
+/*
+ *   This file is part of AnonAccess, an access system which can be used
+ *    to open door or doing other things with an anonymity featured
+ *    account managment.
+ *   Copyright (C) 2006, 2007, 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 
@@ -15,51 +36,54 @@
 #include "sha256.h"
 
 #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"
+
 
 /*
  * SHABEA256-n
  */ 
  
-#define BLOCKSIZE 256
-#define BLOCKSIZEB (BLOCKSIZE/8)
-#define HALFSIZEB  (BLOCKSIZEB/2)
-#define HALFSIZE (BLOCKSIZE/2)
+#define SHABEA_BLOCKSIZE 256
+#define SHABEA_BLOCKSIZEB (SHABEA_BLOCKSIZE/8)
+#define SHABEA_HALFSIZEB  (SHABEA_BLOCKSIZEB/2)
+#define SHABEA_HALFSIZE (SHABEA_BLOCKSIZE/2)
 
 #define L ((uint8_t*)block+ 0)
 #define R ((uint8_t*)block+16)
-void shabea256(void * block, void * key, uint16_t keysize, uint8_t enc, uint8_t rounds){
-	int8_t r;		/**/
-	uint8_t tb[HALFSIZEB+2+(keysize+7)/8];	/**/
+void shabea256(void * block, void * key, uint16_t keysize_b, uint8_t enc, uint8_t rounds){
+	uint8_t r;		/**/
+	uint8_t tb[SHABEA_HALFSIZEB+2+(keysize_b+7)/8];	/**/
 	uint16_t kbs;	/* bytes used for the key / temporary block */
 	sha256_hash_t hash;
+	uint8_t termcond; 
+	int8_t dir;
+	if(enc){
+		r = 0;
+		termcond = rounds-1;
+		dir = 1;
+	} else {
+		r = rounds-1;
+		termcond = 0;
+		dir = -1;
+	}
+	kbs = (keysize_b+7)/8;
+	memcpy(tb+SHABEA_HALFSIZEB+2, key, kbs); /* copy key to temporary block */
+	tb[SHABEA_HALFSIZEB+0] = 0;	/* set round counter high value to zero */
 	
-	r = (enc?0:(rounds-1));
-	kbs = (keysize+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, HALFSIZEB); /* copy right half into tb */
-		tb[HALFSIZEB+1] = r;
-		sha256(&hash, tb, HALFSIZE+16+keysize);
-		if(!(r==(enc?(rounds-1):0))){	
+	for(;;r+=dir){ /* enc: 0..(rounds-1) ; !enc: (rounds-1)..0 */
+		memcpy(tb, R, SHABEA_HALFSIZEB); /* copy right half into tb */
+		tb[SHABEA_HALFSIZEB+1] = r;
+		sha256(&hash, tb, SHABEA_HALFSIZE+16+keysize_b);
+		if(r!=termcond){	
 			/* swap */
-			memxor(hash, L, HALFSIZE);
-			memcpy(L, R, HALFSIZE);
-			memcpy(R, hash, HALFSIZE);
+			memxor(hash, L, SHABEA_HALFSIZEB);
+			memcpy(L, R, SHABEA_HALFSIZEB);
+			memcpy(R, hash, SHABEA_HALFSIZEB);
 		} else {
+			/* last round */
 			/* no swap */
-			memxor(L, hash, HALFSIZE);	
+			memxor(L, hash, SHABEA_HALFSIZEB);
+			return;	
 		}
 	}
 }