forgotten file, my fault

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

diff --git a/arcfour.c b/arcfour.c
index 13fb159e7aff4e559e69e91327935e2feb93aca9..93b2e26bd2e1cd61c34bf8d5bc761c22486b5675 100644 (file)
--- a/arcfour.c
+++ b/arcfour.c
@@ -33,15 +33,16 @@
  * 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;
@@ -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;