oXxtea.js

(function (thiz) {

	
	var O = thiz.O;
     

	O.__.xxTEA = {
	
	
	//
	// 'Block' Tiny Encryption Algorithm xxtea
	// (c) 2002-2006 Chris Veness <scripts@movable-type.co.uk>
	//
	// 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)
	//
	// JavaScript implementation: Chris Veness, Movable Type Ltd: www.movable-type.co.uk
	// http://www.movable-type.co.uk/scripts/TEAblock.html
	//
	// You are welcome to re-use these scripts [without any warranty express or implied] provided
	// you retain my copyright notice and when possible a link to my website (under LGPL license).
	// If you have any queries or find any problems, please contact Chris Veness.
	//
	//
	//
	
	// adapted for O by Francesco Sullo
	
	
		teaencrypt: function (plaintext, key) {
			if (plaintext.length == 0) return('');
			var v = this.strToLongs(escape(plaintext).replace(/%20/g,' '));
			if (v.length <= 1) v[1] = 0;
			var k = this.strToLongs(key.slice(0,16)),
				n = v.length,
				z = v[n-1],
				y = v[0],
				delta = 0x9E3779B9,
				mx,
				e,
				q = Math.floor(6 + 52/n),
				sum = 0;
			while (q-- > 0) {
				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;
				}
			}
	 		return this.escCtrlCh(this.longsToStr(v));
		},
	
		teadecrypt: function (ciphertext, key) {
			if (ciphertext.length == 0) return('');
			var k = this.strToLongs(key.slice(0,16)),
				v = this.strToLongs(this.unescCtrlCh(ciphertext)),
				n = v.length;
			var z = v[n-1], y = v[0], delta = 0x9E3779B9;
			var mx, e, q = Math.floor(6 + 52/n), sum = 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;
			}
			return unescape(this.longsToStr(v).replace(/\0+$/,''));
		},
	
		strToLongs: function (s) {
			var ll = Math.ceil(s.length/4);
			var l = new Array(ll);
			for (var i=0; i<ll; i++) {
				l[i] = s.charCodeAt(i*4)
					+ (s.charCodeAt(i*4+1)<<8)
					+ (s.charCodeAt(i*4+2)<<16)
					+ (s.charCodeAt(i*4+3)<<24);
			}
			return l;
		},
	
		longsToStr: function (l) {
			var a = new Array(l.length);
			for (var i=0; i<l.length; i++) {
				a[i] = String.fromCharCode(
					l[i] & 0xFF,
					l[i]>>>8 & 0xFF,
					l[i]>>>16 & 0xFF,
					l[i]>>>24 & 0xFF
				);
			}
			return a.join('');
		},
	
		escCtrlCh: function (str) {  // escape control chars etc which might cause problems with encrypted texts
	        return str.replace(/[\0\t\n\v\f\r\xa0'"!]/g, function(c) { return '!' + c.charCodeAt(0) + '!'; });
		},
	
		unescCtrlCh: function (str) {  // unescape potentially problematic nulls and control characters
			return str.replace(/!\d\d?\d?!/g, function(c) { return String.fromCharCode(c.slice(1,-1)); });
		}
	
	};



        O.expand({


                fromTEA: function (str,key) {
						return O.__.xxTEA.teadecrypt(
                                str,
                                key
                        );
                },


                toTEA: function (str,key) {
						return O.__.xxTEA.teaencrypt(
                                str,
                                key
                        );
                }

        });



        O.extend({


                fromTEA: function (key) {
						this.O = O.__.xxTEA.teadecrypt(
                                this.O.toString(),
                                key
                        );
                        return this;
                },


                toTEA: function (key) {
                        this.O = O.__.xxTEA.teaencrypt(
                                this.O.toString(),
                                key
                        );
                        return this;
                }

        });

})(this);