C# - DES加密+解密

#region ===========================DES算法===================================
       
        private static string key = "key";
        /// <summary>
        /// 默认加密方法
        /// </summary>
        /// <param name="text"></param>
        /// <returns></returns>
        public static string DESEncrypt(string text)
        {
            return DESEncrypt(text, key);
        }
        /// <summary>
        /// DES加密方法
        /// </summary>
        /// <param name="text">明文</param>
        /// <param name="sKey">密钥</param>
        /// <returns>加密后的密文</returns>
        public static string DESEncrypt(string text,string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray;
            inputByteArray = Encoding.Default.GetBytes(text);
            des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
            des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
            System.IO.MemoryStream ms = new System.IO.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);
            }
            ms.Dispose();
            cs.Dispose();
            return ret.ToString();

        }
        /// <summary>
        /// DES解密方法，默认方法
        /// </summary>
        /// <param name="text">待加密明文</param>
        /// <returns>加密后的密文</returns>
        public static string DESDecrypt(string text)
        {
            return DESDecrypt(text,key);
        }
        /// <summary>
        /// DES解密方法
        /// </summary>
        /// <param name="text">密文</param>
        /// <param name="sKey">密钥</param>
        /// <returns>解密后的明文</returns>
        public static string DESDecrypt(string text,string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            int len;
            len = text.Length / 2;
            byte[] inputByteArray = new byte[len];
            int x, i;
            for (x = 0; x < len; x++)
            {
                i = Convert.ToInt32(text.Substring(x * 2, 2), 16);
                inputByteArray[x] = (byte)i;
            }
            try
            {
                des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
                des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                string estring = Encoding.Default.GetString(ms.ToArray());
                ms.Dispose();
                cs.Dispose();
                return estring;
            }
            catch
            {
                return "";
            }

        } 
        #endregion

        #region ==============================MD5算法==================================
        /// <summary>
        /// 使用MD5算法求Hash散列
        /// </summary>
        /// <param name="text">明文</param>
        /// <returns>散列值</returns>
        public static string MD5Encrypt(string text)
        {
            return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(text, "MD5");
        } 
        #endregion============================================================


        #region =============================SHA1==============================

        /// <summary>
        /// 使用SHA1算法求Hash散列
        /// </summary>
        /// <param name="text">明文</param>
        /// <returns>散列值</returns>
        public static string SHA1Encrypt(string text)
        {
            return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(text, "SHA1");
        } 
        #endregion=============================================================



    }