1：Xxtea支持中文；

2：支持JS和C#加解密之间的互转；

一：C#部分

复制代码 代码如下:
class XXTEA2
{
public static string Encrypt(string source, string key)
{
System.Text.Encoding encoder = System.Text.Encoding.UTF8;
//UTF8==>BASE64==>XXTEA==>BASE64
byte[] bytData = encoder.GetBytes(base64Encode(source));
byte[] bytKey = encoder.GetBytes(key);
if (bytData.Length == 0)
{
return "";
}
return System.Convert.ToBase64String(ToByteArray(Encrypt(ToUInt32Array(bytData, true), ToUInt32Array(bytKey, false)), false));
}
public static string Decrypt(string source, string key)
{
if (source.Length == 0)
{
return "";
}
// reverse
System.Text.Encoding encoder = System.Text.Encoding.UTF8;
byte[] bytData = System.Convert.FromBase64String(source);
byte[] bytKey = encoder.GetBytes(key);

return base64Decode(encoder.GetString(ToByteArray(Decrypt(ToUInt32Array(bytData, false), ToUInt32Array(bytKey, false)), true)));
}

private static UInt32[] Encrypt(UInt32[] v, UInt32[] k)
{
Int32 n = v.Length - 1;
if (n < 1)
{
return v;
}
if (k.Length < 4)
{
UInt32[] Key = new UInt32[4];
k.CopyTo(Key, 0);
k = Key;
}
UInt32 z = v[n], y = v[0], delta = 0x9E3779B9, sum = 0, e;
Int32 p, q = 6 + 52 / (n + 1);
while (q-- > 0)
{
sum = unchecked(sum + delta);
e = sum >> 2 & 3;
for (p = 0; p < n; p++)
{
y = v[p + 1];
z = unchecked(v[p] += (z >> 5 ^ y << 2) + (y >> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z));
}
y = v[0];
z = unchecked(v[n] += (z >> 5 ^ y << 2) + (y >> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z));
}
return v;
}

private static UInt32[] Decrypt(UInt32[] v, UInt32[] k)
{
Int32 n = v.Length - 1;
if (n < 1)
{
return v;
}
if (k.Length < 4)
{
UInt32[] Key = new UInt32[4];
k.CopyTo(Key, 0);
k = Key;
}
UInt32 z = v[n], y = v[0], delta = 0x9E3779B9, sum, e;
Int32 p, q = 6 + 52 / (n + 1);
sum = unchecked((UInt32)(q * delta));
while (sum != 0)
{
e = sum >> 2 & 3;
for (p = n; p > 0; p--)
{
z = v[p - 1];
y = unchecked(v[p] -= (z >> 5 ^ y << 2) + (y >> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z));
}
z = v[n];
y = unchecked(v[0] -= (z >> 5 ^ y << 2) + (y >> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z));
sum = unchecked(sum - delta);
}
return v;
}

private static UInt32[] ToUInt32Array(Byte[] Data, Boolean IncludeLength)
{
Int32 n = (((Data.Length & 3) == 0) ? (Data.Length >> 2) : ((Data.Length >> 2) + 1));
UInt32[] Result;
if (IncludeLength)
{
Result = new UInt32[n + 1];
Result[n] = (UInt32)Data.Length;
}
else
{
Result = new UInt32[n];
}
n = Data.Length;
for (Int32 i = 0; i < n; i++)
{
Result[i >> 2] |= (UInt32)Data[i] << ((i & 3) << 3);
}
return Result;
}

private static Byte[] ToByteArray(UInt32[] Data, Boolean IncludeLength)
{
Int32 n;
if (IncludeLength)
{
n = (Int32)Data[Data.Length - 1];
}
else
{
n = Data.Length << 2;
}
Byte[] Result = new Byte[n];
for (Int32 i = 0; i < n; i++)
{
Result[i] = (Byte)(Data[i >> 2] >> ((i & 3) << 3));
}
return Result;
}

public static string base64Decode(string data)
{
try
{
var encoder = System.Text.Encoding.UTF8;

byte[] todecode_byte = Convert.FromBase64String(data);
return encoder.GetString(todecode_byte);
}
catch (Exception e)
{
throw new Exception("Error in base64Decode" + e.Message);
}
}

public static string base64Encode(string data)
{
try
{
byte[] encData_byte = new byte[data.Length];
encData_byte = System.Text.Encoding.UTF8.GetBytes(data);
string encodedData = Convert.ToBase64String(encData_byte);
return encodedData;
}
catch (Exception e)
{
throw new Exception("Error in base64Encode" + e.Message);
}
}

二：JS部分

//***************************************************************************************
// Autor:Tecky
// var prefix = xt
// update:
//***************************************************************************************

function Xxtea(privateKey) {
this._keyString = privateKey;
}

//将长整形转换为string,private
Xxtea.prototype._long2str = function (v, w) {
var vl = v.length;
var n = (vl - 1) << 2;
if (w) {
var m = v[vl - 1];
if ((m < n - 3) || (m > n)) return null;
n = m;
}
for (var i = 0; i < vl; i++) {
v[i] = String.fromCharCode(v[i] & 0xff,
v[i] >>> 8 & 0xff,
v[i] >>> 16 & 0xff,
v[i] >>> 24 & 0xff);
}
if (w) {
return v.join('').substring(0, n);
}
else {
return v.join('');
}
}

//将string转换为long,private
Xxtea.prototype._str2long = function (s, w) {
var len = s.length;
var v = [];
for (var i = 0; i < len; i += 4) {
v[i >> 2] = s.charCodeAt(i)
| s.charCodeAt(i + 1) << 8
| s.charCodeAt(i + 2) << 16
| s.charCodeAt(i + 3) << 24;
}
if (w) {
v[v.length] = len;
}
return v;
}

//function: encrypt str with private key by xxtea
Xxtea.prototype.xxtea_encrypt = function (str) {
if (str == "") {
return "";
}
str = Base64.encode64(UtfParser.utf16to8(str));
var v = this._str2long(str, true);
var k = this._str2long(this._keyString, false);
if (k.length < 4) {
k.length = 4;
}
var n = v.length - 1;

var z = v[n], y = v[0], delta = 0x9E3779B9;
var mx, e, p, q = Math.floor(6 + 52 / (n + 1)), sum = 0;
while (0 < q--) {
sum = sum + delta & 0xffffffff;
e = sum >>> 2 & 3;
for (p = 0; p < n; p++) {
y = v[p + 1];
mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
z = v[p] = v[p] + mx & 0xffffffff;
}
y = v[0];
mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
z = v[n] = v[n] + mx & 0xffffffff;
}

return Base64.encode64(this._long2str(v, false));
}

//function: decrypt str with private key by xxtea
Xxtea.prototype.xxtea_decrypt = function (str) {
if (str == "") {
return "";
}
str = Base64.decode64(str);
var v = this._str2long(str, false);
var k = this._str2long(this._keyString, false);
if (k.length < 4) {
k.length = 4;
}
var n = v.length - 1;

var z = v[n - 1], y = v[0], delta = 0x9E3779B9;
var mx, e, p, q = Math.floor(6 + 52 / (n + 1)), sum = q * delta & 0xffffffff;
while (sum != 0) {
e = sum >>> 2 & 3;
for (p = n; p > 0; p--) {
z = v[p - 1];
mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
y = v[p] = v[p] - mx & 0xffffffff;
}
z = v[n];
mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
y = v[0] = v[0] - mx & 0xffffffff;
sum = sum - delta & 0xffffffff;
}

return UtfParser.utf8to16(Base64.decode64(this._long2str(v, true)));
}

//Class:utf16 to utf8, utf8 ot utf16
//Author:Tecky
//Date:2008-06-03
function UtfParser() {
//all method is static
}

//function:change utf16 to utf8
//parms(str):string that you want to change
UtfParser.utf16to8 = function (str) {
var out, i, len, c;

out = "";
len = str.length;
for (i = 0; i < len; i++) {
c = str.charCodeAt(i);
if ((c >= 0x0001) && (c <= 0x007F)) {
out += str.charAt(i);
}
else if (c > 0x07FF) {
out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));
out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));
out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
}
else {
out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));
out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
}
}
return out;
}

//function:change utf8 to utf16
//parms(str):string that you want to change
UtfParser.utf8to16 = function (str) {
str = str.toString();

var out, i, len, c;
var char2, char3;

out = "";
len = str.length;
i = 0;
while (i < len) {
c = str.charCodeAt(i++);
switch (c >> 4) {
case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
// 0xxxxxxx
out += str.charAt(i - 1);
break;
case 12: case 13:
// 110x xxxx 10xx xxxx
char2 = str.charCodeAt(i++);
out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
break;
case 14:
// 1110 xxxx 10xx xxxx 10xx xxxx
char2 = str.charCodeAt(i++);
char3 = str.charCodeAt(i++);
out += String.fromCharCode(((c & 0x0F) << 12) |
((char2 & 0x3F) << 6) |
((char3 & 0x3F) << 0));
break;
}
}

return out;
}

// Class:base64 encode & decode
// Autor:Tecky
// Date:2008-06-03
function Base64() {
//all method is static
}

//static
Base64._keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
Base64.encode64 = function (input) {
var output = "";
var chr1, chr2, chr3 = "";
var enc1, enc2, enc3, enc4 = "";
var i = 0;

do {
chr1 = input.charCodeAt(i++);
chr2 = input.charCodeAt(i++);
chr3 = input.charCodeAt(i++);

enc1 = chr1 >> 2;
enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
enc4 = chr3 & 63;

if (isNaN(chr2)) {
enc3 = enc4 = 64;
} else if (isNaN(chr3)) {
enc4 = 64;
}

output = output +
Base64._keyStr.charAt(enc1) +
Base64._keyStr.charAt(enc2) +
Base64._keyStr.charAt(enc3) +
Base64._keyStr.charAt(enc4);
chr1 = chr2 = chr3 = "";
enc1 = enc2 = enc3 = enc4 = "";
} while (i < input.length);

return output;
}

Base64.decode64 = function (input) {
var output = "";
var chr1, chr2, chr3 = "";
var enc1, enc2, enc3, enc4 = "";
var i = 0;

// remove all characters that are not A-Z, a-z, 0-9, +, /, or =
var base64test = /[^A-Za-z0-9\+\/\=\n]/g;
if (base64test.exec(input)) {
alert("There were invalid base64 characters in the input text.\n" +
"Valid base64 characters are A-Z, a-z, 0-9, '+', '/',and '='\n" +
"Expect errors in decoding.");
}
input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

do {
enc1 = Base64._keyStr.indexOf(input.charAt(i++));
enc2 = Base64._keyStr.indexOf(input.charAt(i++));
enc3 = Base64._keyStr.indexOf(input.charAt(i++));
enc4 = Base64._keyStr.indexOf(input.charAt(i++));

chr1 = (enc1 << 2) | (enc2 >> 4);
chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
chr3 = ((enc3 & 3) << 6) | enc4;

output = output + String.fromCharCode(chr1);

if (enc3 != 64) {
output = output + String.fromCharCode(chr2);
}
if (enc4 != 64) {
output = output + String.fromCharCode(chr3);
}

chr1 = chr2 = chr3 = "";
enc1 = enc2 = enc3 = enc4 = "";

} while (i < input.length);

return output;
}
[/code]