c#版本des MD5加密解密算法

        static Encoding encoding = Encoding.UTF8;

        public static string EncryptDES(string encryptString, string key)
        {
            var input = encoding.GetBytes(encryptString);
            var ouptputData = ProcessDES(input, key, true);
            var outputStr = Convert.ToBase64String(ouptputData);

            //base64编码中有不能作为文件名的'/'符号，这里把它替换一下，增强适用范围
            return outputStr;//.Replace('/', '@');
        }

        public static string DecryptDES(string decryptString, string key)
        {
         //   decryptString = decryptString.Replace('@', '/');

            var input = Convert.FromBase64String(decryptString);
            var data = ProcessDES(input, key, false);
            return encoding.GetString(data);
        }


        private static byte[] ProcessDES(byte[] data, string key, bool isEncrypt)
        {
            using (var dCSP = new DESCryptoServiceProvider())
            {
                var keyData = MD5EncodeBytes(key);
                var rgbKey = new ArraySegment<byte>(keyData, 0, 8).ToArray();
                var rgbIV = new ArraySegment<byte>(keyData, 8, 8).ToArray();
                var dCSPKey = isEncrypt ? dCSP.CreateEncryptor(rgbKey, rgbIV) : dCSP.CreateDecryptor(rgbKey, rgbIV);

                using (var memory = new MemoryStream())
                using (var cStream = new CryptoStream(memory, dCSPKey, CryptoStreamMode.Write))
                {
                    cStream.Write(data, 0, data.Length);
                    cStream.FlushFinalBlock();
                    return memory.ToArray();
                }
            }
        }

        /// <summary>
        /// 字符串MD5加密
        /// </summary>
        /// <param name="Text">要加密的字符串</param>
        /// <returns>密文</returns>
        public static string MD5Encode(string Text)
        {
            byte[] buffer = System.Text.Encoding.Default.GetBytes(Text);
            try
            {
                System.Security.Cryptography.MD5CryptoServiceProvider check;
                check = new System.Security.Cryptography.MD5CryptoServiceProvider();
                byte[] somme = check.ComputeHash(buffer);
                string ret = "";
                foreach (byte a in somme)
                {
                    if (a < 16)
                        ret += "0" + a.ToString("X");
                    else
                        ret += a.ToString("X");
                }
                return ret.ToLower();
            }
            catch
            {
                throw;
            }

        }
        public static byte[] MD5EncodeBytes(string str)
        {
            using (var md5 = MD5.Create())
            {
                return md5.ComputeHash(Encoding.UTF8.GetBytes(str));
            }
        }



        /// <summary>  
        /// C# DES加密方法   密钥和向量字符串长度必须为8.
        /// </summary>  
        /// <param name="encryptedValue">要加密的字符串</param>  
        /// <param name="key">密钥</param>  
        /// <param name="iv">向量</param>  
        /// <returns>加密后的字符串</returns>  
        public static string DESEncrypt(string originalValue, string key, string iv)
        {
            using (DESCryptoServiceProvider sa
                = new DESCryptoServiceProvider { Key = Encoding.UTF8.GetBytes(key), IV = Encoding.UTF8.GetBytes(iv) })
            {
                using (ICryptoTransform ct = sa.CreateEncryptor())
                {
                    byte[] by = Encoding.UTF8.GetBytes(originalValue);
                    using (var ms = new MemoryStream())
                    {
                        using (var cs = new CryptoStream(ms, ct,
                                                         CryptoStreamMode.Write))
                        {
                            cs.Write(by, 0, by.Length);
                            cs.FlushFinalBlock();
                        }
                        return Convert.ToBase64String(ms.ToArray());
                    }
                }
            }
        }

        /// <summary>  
        /// C# DES解密方法   密钥和向量字符串长度必须为8.
        /// </summary>  
        /// <param name="encryptedValue">待解密的字符串</param>  
        /// <param name="key">密钥</param>  
        /// <param name="iv">向量</param>  
        /// <returns>解密后的字符串</returns>  
        public static string DESDecrypt(string encryptedValue, string key, string iv)
        {
            using (DESCryptoServiceProvider sa =
                new DESCryptoServiceProvider
                { Key = Encoding.UTF8.GetBytes(key), IV = Encoding.UTF8.GetBytes(iv) })
            {
                using (ICryptoTransform ct = sa.CreateDecryptor())
                {
                    byte[] byt = Convert.FromBase64String(encryptedValue);

                    using (var ms = new MemoryStream())
                    {
                        using (var cs = new CryptoStream(ms, ct, CryptoStreamMode.Write))
                        {
                            cs.Write(byt, 0, byt.Length);
                            cs.FlushFinalBlock();
                        }
                        return Encoding.UTF8.GetString(ms.ToArray());
                    }
                }
            }
        }