new MD5 ins ASM with C (working on pure ASM implementation) plus enhancments in asm...

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

diff --git a/arcfour.c b/arcfour.c
index f8d01a6f12037fca303fd7c105a6a6c7873c9176..5dcb84fb4e4ec7b44e6d34b8c81dbb821ff037c4 100644 (file)
--- a/arcfour.c
+++ b/arcfour.c
@@ -16,16 +16,16 @@
     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:        arcfour.c
  * Author:      Daniel Otte
  * email:       daniel.otte@rub.de
  * Date:        2006-06-07
  * License:     GPLv3 or later
  * Description: Implementation of the ARCFOUR (RC4 compatible) stream cipher algorithm.
- * 
+ *
  */
- 
+
 #include <stdint.h>
 #include "arcfour.h"
 
@@ -33,30 +33,31 @@
  * length is length of key in bytes!
  */
 
-void arcfour_init(arcfour_ctx_t *c, uint8_t *key, uint8_t length){
+void arcfour_init(const void *key, uint8_t length_B, arcfour_ctx_t *ctx){
        uint8_t t;
-       unsigned x,y=0;
+       uint16_t x,y=0;
        for(x=0; x<= 255; ++x)
-               c->s[x]=x;
-       
+               ctx->s[x]=x;
+
        for(x=0; x<= 255; ++x){
-               y += c->s[x] + key[x % length];
+               y += ctx->s[x] + ((uint8_t*)key)[x % length_B];
                y &= 0xff;
-               t = c->s[y];
-               c->s[y] = c->s[x];
-               c->s[x] = t;
-       };
-               
-       c->i = c->j = 0;
+               /* ctx->s[y] <--> ctx->s[x] */
+               t = ctx->s[y];
+               ctx->s[y] = ctx->s[x];
+               ctx->s[x] = t;
+       }
+       ctx->i = ctx->j = 0;
 }
 
-uint8_t arcfour_gen(arcfour_ctx_t *c){
+uint8_t arcfour_gen(arcfour_ctx_t *ctx){
        uint8_t t;
-       c->i++;
-       c->j += c->s[c->i];
-       t = c->s[c->j];
-       c->s[c->j] = c->s[c->i];
-       c->s[c->i] = t;
-       return c->s[(c->s[c->j] + c->s[c->i]) & 0xff];
+       ctx->i++;
+       ctx->j += ctx->s[ctx->i];
+       /* ctx->s[i] <--> ctx->s[j] */
+       t = ctx->s[ctx->j];
+       ctx->s[ctx->j] = ctx->s[ctx->i];
+       ctx->s[ctx->i] = t;
+       return ctx->s[(ctx->s[ctx->j] + ctx->s[ctx->i]) & 0xff];
 }