DESC 加密，解密

一、加密解密方法

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Web;

namespace MvcApplication1.Helper
{
    public class CryptoSecurity
    {
        /// <summary>
        /// 对地址加密
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public static string UrlEncode(string url)
        {
            string[] str = url.Split('?');
            return str[0] + "?" + Encode(str[1]) + ".shtml";
        }

        /// <summary>
        /// 对地址解密
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public static string[] UrlDecode(string url)
        {
            string[] urls = new string[2];
            try
            {
                string[] str = url.Split('?');
                urls[0] = str[0];
                urls[1] = Decode(str[1].Split('.')[0]);
                return urls;
            }
            catch
            {
                urls[0] = "/Home/Error";
                urls[1] = "";
                return urls;
            }
        }

        private static string key = DateTime.Now.ToString(yyMMdd) + "1jjqsd789";
        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string Encode(string str)
        {
            DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
            provider.Key = Encoding.ASCII.GetBytes(key.Substring(0, 8));
            provider.IV = Encoding.ASCII.GetBytes(key.Substring(0, 8));
            byte[] bytes = Encoding.GetEncoding("GB2312").GetBytes(str);
            MemoryStream stream = new MemoryStream();
            CryptoStream stream2 = new CryptoStream(stream, provider.CreateEncryptor(), CryptoStreamMode.Write);
            stream2.Write(bytes, 0, bytes.Length);
            stream2.FlushFinalBlock();
            StringBuilder builder = new StringBuilder();
            foreach (byte num in stream.ToArray())
            {
                builder.AppendFormat("{0:X2}", num);
            }
            stream.Close();
            return builder.ToString();
        }

        /// <summary>
        /// Des 解密 GB2312 
        /// </summary>
        /// <param name="str">Desc string</param>
        /// <returns></returns>
        public static string Decode(string str)
        {
            DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
            provider.Key = Encoding.ASCII.GetBytes(key.Substring(0, 8));
            provider.IV = Encoding.ASCII.GetBytes(key.Substring(0, 8));
            byte[] buffer = new byte[str.Length / 2];
            for (int i = 0; i < (str.Length / 2); i++)
            {
                int num2 = Convert.ToInt32(str.Substring(i * 2, 2), 0x10);
                buffer[i] = (byte)num2;
            }
            MemoryStream stream = new MemoryStream();
            CryptoStream stream2 = new CryptoStream(stream, provider.CreateDecryptor(), CryptoStreamMode.Write);
            stream2.Write(buffer, 0, buffer.Length);
            stream2.FlushFinalBlock();
            stream.Close();
            return Encoding.GetEncoding("GB2312").GetString(stream.ToArray());
        }
    }
}

二、global.aspx文件

        public void URLRewriting()
        {
            string AllUrl = Request.RawUrl.ToString();
            if (AllUrl.Contains(".shtml"))
            {
                string[] urls = CryptoSecurity.UrlDecode(AllUrl);
                Context.RewritePath(urls[0], String.Empty, urls[1]);
            }
        }
        public void Application_BeginRequest(Object sender, EventArgs e)
        {
            URLRewriting();
        }