X-Git-Url: https://git.cryptolib.org/?p=avr-crypto-lib.git;a=blobdiff_plain;f=shabea%2Fshabea.c;fp=shabea%2Fshabea.c;h=b59e138e23ca13f2569def3ac5f029649d196b3b;hp=0000000000000000000000000000000000000000;hb=d32eba56ce10ea6b9eff123b50d9842673b38f2b;hpb=8f855d283a31a468ea014774c4723a8b77b81644

diff --git a/shabea/shabea.c b/shabea/shabea.c
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+/* 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 
+ * \date	2007-06-07
+ * \brief	SHABEA - a SHA Based Encryption Algorithm implementation
+ * \par License	
+ * GPL
+ * 
+ * SHABEAn-r where n is the blocksize and r the number of round used
+ * 
+ * 
+ */
+#include <stdlib.h>
+#include <string.h>
+#include "sha256.h"
+
+#include "config.h"
+#include "memxor.h"
+
+
+/*
+ * SHABEA256-n
+ */ 
+ 
+#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_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 */
+	
+	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, SHABEA_HALFSIZEB);
+			memcpy(L, R, SHABEA_HALFSIZEB);
+			memcpy(R, hash, SHABEA_HALFSIZEB);
+		} else {
+			/* last round */
+			/* no swap */
+			memxor(L, hash, SHABEA_HALFSIZEB);
+			return;	
+		}
+	}
+}
+
+