X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=arcfour%2Farcfour.c;h=ba66c165dd44e89e2d5691b2c3b0414fbe3b1d9f;hb=701cee0d98aab48dd3192c8cc7c77eb42581bc56;hp=e07193f2cbfbc9564adff1557c4f78b3b1ed414e;hpb=d32eba56ce10ea6b9eff123b50d9842673b38f2b;p=avr-crypto-lib.git

diff --git a/arcfour/arcfour.c b/arcfour/arcfour.c
index e07193f..ba66c16 100644
--- a/arcfour/arcfour.c
+++ b/arcfour/arcfour.c
@@ -33,20 +33,29 @@
  * length is length of key in bytes!
  */
 
-void arcfour_init(const void *key, uint8_t length_B, arcfour_ctx_t *ctx){
+void arcfour_init(const void *key, uint16_t length_b, arcfour_ctx_t *ctx){
 	uint8_t t;
-	uint16_t x,y=0;
-	for(x=0; x<= 255; ++x)
+	const uint8_t length_B = length_b/8;
+	uint8_t nidx = length_B;
+	uint8_t x=0,y=0;
+	const uint8_t *kptr = (const uint8_t*)key;
+	do{
 		ctx->s[x]=x;
+	}while((uint8_t)++x);
 
-	for(x=0; x<= 255; ++x){
-		y += ctx->s[x] + ((uint8_t*)key)[x % length_B];
+	do{
+		y += ctx->s[x] + *kptr++;
+		if(!--nidx){
+			kptr = (const uint8_t*)key;
+			nidx = length_B;
+		}
 		y &= 0xff;
 		/* ctx->s[y] <--> ctx->s[x] */
 		t = ctx->s[y];
 		ctx->s[y] = ctx->s[x];
 		ctx->s[x] = t;
-	}
+	}while((uint8_t)++x);
+
 	ctx->i = ctx->j = 0;
 }