/*
 *	RC4 Symmetric Cipher Encryption
 *
 */

function rc4_encrypt(key, pt) {
	s = new Array();
	for (var i=0; i<256; i++) {
		s[i] = i;
	}
	var j = 0;
	var x;
	for (i=0; i<256; i++) {
		j = (j + s[i] + key.charCodeAt(i % key.length)) % 256;
		x = s[i];
		s[i] = s[j];
		s[j] = x;
	}
	i = 0;
	j = 0;
	var ct = '';
	for (var y=0; y<pt.length; y++) {
		i = (i + 1) % 256;
		j = (j + s[i]) % 256;
		x = s[i];
		s[i] = s[j];
		s[j] = x;
		ct += String.fromCharCode(pt.charCodeAt(y) ^ s[(s[i] + s[j]) % 256]);
	}
	return ct;
}

/* decryption */
function rc4_decrypt(key, ct) {
	return rc4_encrypt(key, ct);
}