/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Licensed under a Creative Creative Commons Attribution 3.0 Unported License */
/* without any warranty express or implied */
/* http://creativecommons.org/licenses/by/3.0/ */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Block TEA (xxtea) Tiny Encryption Algorithm implementation in ActionScript */
/* (c) Wowza Media Systems, Inc 2010: www.wowzamedia.com */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Block TEA (xxtea) Tiny Encryption Algorithm implementation in JavaScript */
/* (c) Chris Veness 2002-2010: www.movable-type.co.uk/tea-block.html */
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
/* Algorithm: David Wheeler & Roger Needham, Cambridge University Computer Lab */
/* http://www.cl.cam.ac.uk/ftp/papers/djw-rmn/djw-rmn-tea.html (1994) */
/* http://www.cl.cam.ac.uk/ftp/users/djw3/xtea.ps (1997) */
/* http://www.cl.cam.ac.uk/ftp/users/djw3/xxtea.ps (1998) */
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
package com.wowza.encryptionAS3 {
public class TEA {
/*
* encrypt text using Corrected Block TEA (xxtea) algorithm
*
* @param {string} plaintext String to be encrypted (multi-byte safe)
* @param {string} password Password to be used for encryption (1st 16 chars)
* @returns {string} encrypted text
*/
public static function encrypt(plaintext:String, password:String):String {
if (plaintext.length == 0) return ""; // nothing to encrypt
// convert string to array of longs after converting any multi-byte chars to UTF-8
var v:Array = charsToLongs(strToChars(plaintext));
if (v.length <= 1) v[1] = 0; // algorithm doesn't work for n<2 so fudge by adding a null
// simply convert first 16 chars of password as key
var k:Array = charsToLongs(strToChars(password.substr(0, 16)));
var n:Number = v.length;
// ---- ----
var z:Number = v[n-1], y:Number = v[0], delta:Number = 0x9E3779B9;
var mx:Number, e:Number, q:Number = Math.floor(6 + 52/n), sum:Number = 0;
while (q-- > 0) { // 6 + 52/n operations gives between 6 & 32 mixes on each word
sum += delta;
e = sum>>>2 & 3;
for (var p = 0; p < n; p++) {
y = v[(p+1)%n];
mx = (z>>>5 ^ y<<2) + (y>>>3 ^ z<<4) ^ (sum^y) + (k[p&3 ^ e] ^ z);
z = v[p] += mx;
}
}
// ---- ----
var ciphertext:Array = longsToChars(v);
return charsToHex(ciphertext);
}
/*
* decrypt text using Corrected Block TEA (xxtea) algorithm
*
* @param {string} ciphertext String to be decrypted
* @param {string} password Password to be used for decryption (1st 16 chars)
* @returns {string} decrypted text
*/
public static function decrypt(ciphertext:String, password:String):String {
if (ciphertext.length == 0) return "";
var v:Array = charsToLongs(hexToChars(ciphertext));
var k:Array = charsToLongs(strToChars(password.substr(0, 16)));
var n:Number = v.length;
// ---- ----
var z:Number = v[n-1], y:Number = v[0], delta:Number = 0x9E3779B9;
var mx:Number, e:Number, q:Number = Math.floor(6 + 52/n), sum:Number = q*delta;
while (sum != 0) {
e = sum>>>2 & 3;
for (var p = n-1; p >= 0; p--) {
z = v[p>0 ? p-1 : n-1];
mx = (z>>>5 ^ y<<2) + (y>>>3 ^ z<<4) ^ (sum^y) + (k[p&3 ^ e] ^ z);
y = v[p] -= mx;
}
sum -= delta;
}
// ---- ----
var plaintext:Array = longsToChars(v);
return charsToStr(plaintext);
}
/**
* Private methods.
*/
private static function charsToLongs(chars:Array):Array {
var temp:Array = new Array(Math.ceil(chars.length/4));
for (var i:Number = 0; i>>8 & 0xFF, longs[i]>>>16 & 0xFF, longs[i]>>>24 & 0xFF);
}
return codes;
}
private static function longToChars(longs:Number):Array {
var codes:Array = new Array();
codes.push(longs & 0xFF, longs>>>8 & 0xFF, longs>>>16 & 0xFF, longs>>>24 & 0xFF);
return codes;
}
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> 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