X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=arcfour.c;h=5dcb84fb4e4ec7b44e6d34b8c81dbb821ff037c4;hb=12883cff6e7d233365e8477e08f90c75fa5a48b2;hp=13fb159e7aff4e559e69e91327935e2feb93aca9;hpb=4d76909e4282baf1420ee309e270384246b241b8;p=avr-crypto-lib.git

diff --git a/arcfour.c b/arcfour.c
index 13fb159..5dcb84f 100644
--- 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"
 
@@ -33,19 +33,20 @@
  * length is length of key in bytes!
  */
 
-void arcfour_init(arcfour_ctx_t *ctx, void *key, uint8_t length_B){
+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)
 		ctx->s[x]=x;
-	
+
 	for(x=0; x<= 255; ++x){
 		y += ctx->s[x] + ((uint8_t*)key)[x % length_B];
 		y &= 0xff;
+		/* 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;
 }
 
@@ -53,6 +54,7 @@ uint8_t arcfour_gen(arcfour_ctx_t *ctx){
 	uint8_t t;
 	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;