如何对COOKIES加密解密？

加密 Cookies
Response.Cookies["askCRM"]["USERID"] = Tools.Encrypt(strUserName.Trim(), Tools.myKey);
解密
string strUid = Request.Cookies["askCRM"]["USERID"];
strUid = Tools.Decrypt(strUid, Tools.myKey);

加密解密 掉用的方法
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Security.Cryptography;
using System.IO;
using System.Text;

/// <summary>
/// Tools 的摘要说明

/// </summary>
public class Tools
{

/// <summary>
/// 当前程序加密所使用的密钥

/// </summary>
public static readonly string myKey = "q0m3sd8l";

#region 加密方法
/// <summary>
/// 加密方法
/// </summary>
/// <param name="pToEncrypt">需要加密字符串</param>
/// <param name="sKey">密钥</param>
/// <returns>加密后的字符串</returns>
public static string Encrypt(string pToEncrypt, string sKey)
{
try
{
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
//把字符串放到byte数组中

//原来使用的UTF8编码，我改成Unicode编码了，不行
byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);

//建立加密对象的密钥和偏移量

//使得输入密码必须输入英文文本
des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();
StringBuilder ret = new StringBuilder();
foreach (byte b in ms.ToArray())
{
ret.AppendFormat("{0:X2}", b);
}
ret.ToString();
return ret.ToString();
}
catch (Exception ex)
{
JS.Alert("写入配置信息失败，详细信息：" + ex.Message.Replace("/r/n", "").Replace("'", ""));
}

return "";
}
#endregion

#region 解密方法
/// <summary>
/// 解密方法
/// </summary>
/// <param name="pToDecrypt">需要解密的字符串</param>
/// <param name="sKey">密匙</param>
/// <returns>解密后的字符串</returns>
public static string Decrypt(string pToDecrypt, string sKey)
{
try
{
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
for (int x = 0; x < pToDecrypt.Length / 2; x++)
{
int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
inputByteArray[x] = (byte)i;
}

//建立加密对象的密钥和偏移量，此值重要，不能修改
des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();
//建立StringBuild对象，CreateDecrypt使用的是流对象，必须把解密后的文本变成流对象
StringBuilder ret = new StringBuilder();
return System.Text.Encoding.Default.GetString(ms.ToArray());
}
catch (Exception ex)
{
JS.Alert("读取配置信息失败，详细信息：" + ex.Message.Replace("/r/n", "").Replace("'", ""));
}
return "";
}
#endregion
}