insereated GPLv3 stub

[avr-crypto-lib.git] / shabea.c

diff --git a/shabea.c b/shabea.c
index e2604e1f0b5af3522457eb1772e5fc9930107a7a..62ff6b4a27e72b5af76223f3e8c06f09bd2df6de 100644 (file)
--- a/shabea.c
+++ b/shabea.c
@@ -1,8 +1,26 @@
+/* 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
  * 
@@ -27,37 +45,41 @@ void memxor(uint8_t * dest, uint8_t * src, uint8_t length){
 } 
 
 /*
- * 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, uint8_t enc, uint8_t rounds){
        int8_t r;               /**/
-       uint8_t *tb;    /**/
+       uint8_t tb[HALFSIZEB+2+(keysize+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+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);
                if(!(r==(enc?(rounds-1):0))){   
                        /* swap */
-                       memxor(hash, L, 8);
-                       memcpy(L, R, 8);
-                       memcpy(R, hash, 8);
+                       memxor(hash, L, HALFSIZE);
+                       memcpy(L, R, HALFSIZE);
+                       memcpy(R, hash, HALFSIZE);
                } else {
                        /* no swap */
-                       memxor(L, hash, 8);     
+                       memxor(L, hash, HALFSIZE);      
                }
        }
-       free(tb);
 }