#include "StdAfx.h"
#include <stdio.h>

void swapints(int *array, int ndx1, int ndx2)
{
    int temp = array[ndx1];
    array[ndx1] = array[ndx2];
    array[ndx2] = temp;
}

void EnDeCrypt(const char *lpbufin, int ibufinLen,   char *lpbufout, int ibufoutLen, const char *pszKey)
{
    int a, b, i=0, j=0, k;              
    int ilen;                           
    int sbox[256];                      
    int key [256];                       

    ilen = strlen(pszKey);
    for (a=0; a < 256; a++){
        key[a] = pszKey[a % ilen];
        sbox[a] = a;
    }
    for (a=0, b=0; a < 256; a++){
        b = (b + sbox[a] + key[a]) % 256;
        swapints(sbox, a, b);
    }
    for (a=0; a < ibufinLen; a++){
        i = (i + 1) % 256;
        j = (j + sbox[i]) % 256;
        swapints(sbox, i, j);
        k = sbox[(sbox[i] + sbox[j]) % 256];
        lpbufout[a] = lpbufin[a] ^ k;
    }
    return;
}

#define RC4PUBLICKEY "xtryiroeb"
int RC4EnCrypt(  const char *lpbufin, int  bufinLen, char *lpbufout,  int bufoutLen )
{
	if ( lpbufin && bufinLen > 0 && lpbufout && bufoutLen > 0 ){
		EnDeCrypt( lpbufin, bufinLen, lpbufout, bufoutLen, RC4PUBLICKEY );
		return 0;
	}
	return 1;
}

int RC4DeCrypt(  const char *lpbufin, int  bufinLen, char *lpbufout,  int bufoutLen )
{
	if ( lpbufin && bufinLen > 0 && lpbufout && bufoutLen > 0 ){
		EnDeCrypt( lpbufin, bufinLen, lpbufout, bufoutLen, RC4PUBLICKEY );
		return 0;
	}	
	return 1;
}