asp.net中的DES加密解密

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Security.Cryptography;
using System.IO;

namespace XYDWXTWeb
{
    public partial class DES : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            //string EnPswdStr = Encode(TextBox2.Text);
            string EnPswdStr = Encode(TextBox2.Text);
            //显示出来   
            TextBox1.Text = EnPswdStr;
        }
        public static string _KEY = "HQDCKEY1";  //**  
        public static string _IV = "HQDCKEY2";   //向量  
        public static string Encode(string data)
        {

            byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(_KEY);
            byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(_IV);

            DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
            int i = cryptoProvider.KeySize;
            MemoryStream ms = new MemoryStream();
            CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);
            StreamWriter sw = new StreamWriter(cst);
            sw.Write(data);
            sw.Flush();
            cst.FlushFinalBlock();
            sw.Flush();
            string strRet = Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);
            return strRet;
        }  
        //public static string _KEY = "HQDCKEY1";  //**  
        //public static string _IV = "HQDCKEY2";   //向量  
        //public static string Decode(string data)
        //{

        //    byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(_KEY);
        //    byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(_IV);

        //    byte[] byEnc;

        //    try
        //    {
        //        data.Replace("_%_", "/");
        //        data.Replace("-%-", "#");
        //        byEnc = Convert.FromBase64String(data);

        //    }
        //    catch
        //    {
        //        return null;
        //    }

        //    DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
        //    MemoryStream ms = new MemoryStream(byEnc);
        //    CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);
        //    StreamReader sr = new StreamReader(cst);
        //    return sr.ReadToEnd();
        //} 
    }
}

注：注释掉的为解密方法