//加密方法
private string encrypt(string strToEncrypt)
{
    if (strToEncrypt == null || strToEncrypt == "") return strToEncrypt;
    DESCryptoServiceProvider des = new DESCryptoServiceProvider();
    //把字符串放到byte數(shù)組中，主意編碼方式
    byte[] inputByteArray = Encoding.Default.GetBytes(strToEncrypt);
    //建立加密對象的密鑰和偏移量
    des.Key = new byte[] { 1, 3, 5, 7, 2, 4, 6, 8 };
    des.Mode = CipherMode.ECB;
    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);
    }
    return ret.ToString();
}
//解密方法
private string Decrypt(string pToDecrypt)
{
    if (pToDecrypt == null || pToDecrypt == "") return pToDecrypt;
    try
    {
      DESCryptoServiceProvider des = new DESCryptoServiceProvider();
      //Put the input string into the byte array
      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;
      }
      //key
      des.Key = new byte[] { 1, 3, 5, 7, 2, 4, 6, 8 }; ;
      //des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
      des.Mode = CipherMode.ECB;
      MemoryStream ms = new MemoryStream();
      CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
      cs.Write(inputByteArray, 0, inputByteArray.Length);
      cs.FlushFinalBlock();
      //建立StringBuild對象，CreateDecrypt使用的是流對象，必須把解密后的文本變成流對象
      StringBuilder ret = new StringBuilder();
      return System.Text.Encoding.Default.GetString(ms.ToArray());
    }
    catch (Exception Exp)
    {
      return String.Empty;
    }
}