密码加密解密

  /// <summary>
        /// 密码加密
        /// </summary>
        /// <param name="PasswordString">密码</param>
        /// <param name="PasswordFormat">加密类型[SHA1],[MD5]</param>
        /// <returns></returns>
        public static string  EncryptPassword(string PasswordString, string PasswordFormat)
        {
            string encryptPassword = null;
            if (PasswordFormat == "SHA1")
            {
                encryptPassword =FormsAuthentication.HashPasswordForStoringInConfigFile(PasswordString, "SHA1");
            }
            else if (PasswordFormat == "MD5")
            {
                encryptPassword = FormsAuthentication.HashPasswordForStoringInConfigFile(PasswordString, "MD5");
            }
            return encryptPassword;
        }

  /// <summary>
        /// DES解密字符串
        /// </summary>
        /// <param name="decryptString">待解密的字符串</param>
        /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
        /// <returns>解密成功返回解密后的字符串，失败返源串</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;
            }
        }