数据加密3(不可逆)

/// <summary>
  /// 加密字符串，使用不同加密方法
  /// </summary>
  /// <param name="stringToEncrypt">encrypting string</param>
  /// <param name="encryptMethod">format,0 is SHA1,1 is MD5</param>
  /// <returns></returns>
  public static string Encrypt(string stringToEncrypt,int encryptMethod)
  {
   string str = "";
   switch(encryptMethod)
   {
    case 0:
     str = FormsAuthentication.HashPasswordForStoringInConfigFile(stringToEncrypt,"SHA1");
     break;
    case 1:
     str = FormsAuthentication.HashPasswordForStoringInConfigFile(stringToEncrypt,"MD5");
     break;
   }
   return str;
  }