asp.net DES加解密

对称加密DES，用来加解密。（MD5非对称加密无法解密，一般用来加密密码，登录时加密对比字符串） 

/// <summary>
    /// 对称DES加密解密
    /// </summary>
    public class DESEncrypt
    {

        //自定义口令
        private static string key = "1dowbndk";

        /// <summary>
        /// 对称加密解密的**
        /// </summary>
        public static string Key
        {
            get
            {
                return key;
            }
            set
            {
                key = value;
            }
        }

        /// <summary>
        /// DES加密
        /// </summary>
        /// <param name="encryptString"></param>
        /// <returns></returns>
        public static string DesEncrypt(string encryptString)
        {
            try
            {
                byte[] keyBytes = Encoding.UTF8.GetBytes(key.Substring(0, 8));
                byte[] keyIV = keyBytes;
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, provider.CreateEncryptor(keyBytes, keyIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                string result= Convert.ToBase64String(mStream.ToArray());
                mStream.Close();
                cStream.Close();
                return result;
            }
            catch (Exception)
            {
                return "";
            }
        }

        /// <summary>
        /// DES解密
        /// </summary>
        /// <param name="decryptString"></param>
        /// <returns></returns>
        public static string DesDecrypt(string decryptString)
        {
            try
            {
                byte[] keyBytes = Encoding.UTF8.GetBytes(key.Substring(0, 8));
                byte[] keyIV = keyBytes;
                byte[] inputByteArray = Convert.FromBase64String(decryptString);
                DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, provider.CreateDecryptor(keyBytes, keyIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                string result = Encoding.UTF8.GetString(mStream.ToArray());
                mStream.Close();
                cStream.Close();
                return result;
            }
            catch (Exception)
            {
                return "";
            }
        }
    }