public class DesEncrypt  {    /// <summary>    /// 算法偏移量    /// </summary>    const string m_IV = "12345678";     /// <summary>    /// 功能描述:根據輸入的密鑰生成8位密鑰    /// 作　　者: 愛給模板網 2gei.cn    /// 創建日期:2015-07-20 17:25:26    /// </summary>    /// <param name="strkey">strkey</param>    /// <returns>8位密鑰</returns>    private static string GetKey(string strkey)    {      if (string.IsNullOrEmpty(strkey))      {        strkey = "InfoColl";      }      if (strkey.Length % 8 == 0)      {        return strkey;      }      else      {        return GetKey(strkey + "0");      }    }     /// <summary>    /// 功能描述:加密字符串    /// 作　　者: 愛給模板網 2gei.cn    /// 創建日期:2015-07-20 17:18:31    /// 任務編號:    /// </summary>    /// <param name="strSourceString">原字符串</param>    /// <param name="strKey">密鑰</param>    /// <returns>加密后的字符串</returns>    public static string Encrypt(string strSourceString, string strKey)    {      strKey = GetKey(strKey);      byte[] btKey = Encoding.UTF8.GetBytes(strKey);       byte[] btIV = Encoding.UTF8.GetBytes(m_IV);       DESCryptoServiceProvider des = new DESCryptoServiceProvider();       using (MemoryStream ms = new MemoryStream())      {        try        {          byte[] inData = Encoding.UTF8.GetBytes(strSourceString);          using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write))          {            cs.Write(inData, 0, inData.Length);             cs.FlushFinalBlock();          }           return Convert.ToBase64String(ms.ToArray());        }        catch        {          return strSourceString;        }      }    }     /// <summary>    /// 功能描述:解密字符串    /// 作　　者: 愛給模板網 2gei.cn    /// 創建日期:2015-07-20 17:18:49    /// 任務編號:    /// </summary>    /// <param name="strEncryptedString">原字符串</param>    /// <param name="strKey">密鑰</param>    /// <returns>解密后的字符串</returns>    public static string Decrypt(string strEncryptedString, string strKey)    {      strKey = GetKey(strKey);      byte[] btKey = Encoding.UTF8.GetBytes(strKey);       byte[] btIV = Encoding.UTF8.GetBytes(m_IV);       DESCryptoServiceProvider des = new DESCryptoServiceProvider();       using (MemoryStream ms = new MemoryStream())      {        try        {          byte[] inData = Convert.FromBase64String(strEncryptedString);          using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write))          {            cs.Write(inData, 0, inData.Length);             cs.FlushFinalBlock();          }           return Encoding.UTF8.GetString(ms.ToArray());        }        catch        {          return strEncryptedString;        }      }    }  }

using System.Security.Cryptography;using System.IO;//默認密鑰向量    private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };    /// <summary>    /// DES加密字符串    /// </summary>    /// <param name="encryptString">待加密的字符串</param>    /// <param name="encryptKey">加密密鑰,要求為8位</param>    /// <returns>加密成功返回加密后的字符串，失敗返回源串 </returns>    public static string EncryptDES(string encryptString, string encryptKey)    {      try      {        byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));//轉換為字節        byte[] rgbIV = Keys;        byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);        DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();//實例化數據加密標準        MemoryStream mStream = new MemoryStream();//實例化內存流        //將數據流鏈接到加密轉換的流        CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);        cStream.Write(inputByteArray, 0, inputByteArray.Length);        cStream.FlushFinalBlock();        return Convert.ToBase64String(mStream.ToArray());      }      catch      {        return encryptString;      }    }    /// <summary>    /// DES解密字符串    /// </summary>    /// <param name="decryptString">待解密的字符串</param>    /// <param name="decryptKey">解密密鑰,要求為8位,和加密密鑰相同</param>    /// <returns>解密成功返回解密后的字符串，失敗返源串</returns>    public static string DecryptDES(string decryptString, string decryptKey)    {      try      {        byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);        byte[] rgbIV = Keys;        byte[] inputByteArray = Convert.FromBase64String(decryptString);        DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();        MemoryStream mStream = new MemoryStream();        CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);        cStream.Write(inputByteArray, 0, inputByteArray.Length);        cStream.FlushFinalBlock();        return Encoding.UTF8.GetString(mStream.ToArray());      }      catch      {        return decryptString;      }    }      string EncryptStr = EncryptDESString.EncryptDES("aaaaaaaaaa", "ssssssss"); //返回加密后的字符串      string DecryptStr = EncryptDESString.DecryptDES(EncryptStr, "ssssssss");//解密字符串