rc4.c

Go to the documentation of this file.

//#include "stdafx.h"
#include "rc4.h"
 
 
void  rc4_init(unsigned char *state, unsigned char *key, int len)
{
    //FYI state = unsigned char rc4[0x100];
 
    int i, j=0, t; 
 
    for (i=0; i < 256; ++i)
        state[i] = i; 
 
    for (i=0; i < 256; ++i) {
        j = (j + state[i] + key[i % len]) % 256; 
        t = state[i]; 
        state[i] = state[j]; 
        state[j] = t; 
    }   
}
 
void  rc4_crypt(unsigned char *state, unsigned char *data, int len)
{  
    //FYI state = unsigned char rc4[0x100];
    
    int i=0,j=0,x,t; 
 
    for (x=0; x < len; ++x)  {
        i = (i + 1) % 256;
        j = (j + state[i]) % 256;
        t = state[i];
        state[i] = state[j];
        state[j] = t;
        *data++ ^= state[(state[i] + state[j]) % 256];
    }
}