/**
* Encrypts and decrypts an alleged RC4 hash.
* @author Mika Palmu
* @version 1.0
*
* Orginal Flash port by:
* Gabor Penoff - http://www.fns.hu
* Email: fns@fns.hu
*/
class com.meychi.ascrypt.RC4 {
/**
* Variables
* @exclude
*/
private static var sbox:Array = new Array(255);
private static var mykey:Array = new Array(255);
/**
* Encrypts a string with the specified key.
*/
public static function encrypt(src:String, key:String):String {
var mtxt:Array = strToChars(src);
var mkey:Array = strToChars(key);
var result:Array = calculate(mtxt, mkey);
return charsToHex(result);
}
/**
* Decrypts a string with the specified key.
*/
public static function decrypt(src:String, key:String):String {
var mtxt:Array = hexToChars(src);
var mkey:Array = strToChars(key);
var result:Array = calculate(mtxt, mkey);
return charsToStr(result);
}
/**
* Private methods.
*/
private static function initialize(pwd:Array) {
var b:Number = 0;
var tempSwap:Number;
var intLength:Number = pwd.length;
for (var a:Number = 0; a <= 255; a++) {
mykey[a] = pwd[(a%intLength)];
sbox[a] = a;
}
for (var a:Number=0; a<=255; a++) {
b = (b+sbox[a]+mykey[a]) % 256;
tempSwap = sbox[a];
sbox[a] = sbox[b];
sbox[b] = tempSwap;
}
}
private static function calculate(plaintxt:Array, psw:Array):Array {
initialize(psw);
var i:Number = 0; var j:Number = 0;
var cipher:Array = new Array();
var k:Number, temp:Number, cipherby:Number;
for (var a:Number = 0; a<plaintxt.length; a++) {
i = (i+1) % 256;
j = (j+sbox[i])%256;
temp = sbox[i];
sbox[i] = sbox[j];
sbox[j] = temp;
var idx:Number = (sbox[i]+sbox[j]) % 256;
k = sbox[idx];
cipherby = plaintxt[a]^k;
cipher.push(cipherby);
}
return cipher;
}
private static function charsToHex(chars:Array):String {
var result:String = new String("");
var hexes:Array = new Array("0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f");
for (var i:Number = 0; i<chars.length; i++) {
result += hexes[chars[i] >> 4] + hexes[chars[i] & 0xf];
}
return result;
}
private static function hexToChars(hex:String):Array {
var codes:Array = new Array();
for (var i:Number = (hex.substr(0, 2) == "0x") ? 2 : 0; i<hex.length; i+=2) {
codes.push(parseInt(hex.substr(i, 2), 16));
}
return codes;
}
private static function charsToStr(chars:Array):String {
var result:String = new String("");
for (var i:Number = 0; i<chars.length; i++) {
result += String.fromCharCode(chars[i]);
}
return result;
}
private static function strToChars(str:String):Array {
var codes:Array = new Array();
for (var i:Number = 0; i<str.length; i++) {
codes.push(str.charCodeAt(i));
}
return codes;
}
}