forgotten files

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

diff --git a/shabea.c b/shabea.c
index 7acb4d3f9b9be78a2b2d80a5657e3208a2cba3e2..b59e138e23ca13f2569def3ac5f029649d196b3b 100644 (file)
--- 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; 
                }
        }
 }