Crypter et Décrypter en C#

        public string encrypt(string message)
        {
            byte[] results;
            string passphrase = "Password123";
            UTF8Encoding utf8 = new UTF8Encoding();
            //to create the object for UTF8Encoding  class
            //TO create the object for MD5CryptoServiceProvider
            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            byte[] deskey = md5.ComputeHash(utf8.GetBytes(passphrase));
            //to convert to binary passkey
            //TO create the object for  TripleDESCryptoServiceProvider
            TripleDESCryptoServiceProvider desalg = new TripleDESCryptoServiceProvider();
            desalg.Key = deskey;//to  pass encode key
            desalg.Mode = CipherMode.ECB;
            desalg.Padding = PaddingMode.PKCS7;
            byte[] encrypt_data = utf8.GetBytes(message);
            //to convert the string to utf encoding binary

            try
            {
                //To transform the utf binary code to md5 encrypt   
                ICryptoTransform encryptor = desalg.CreateEncryptor();
                results = encryptor.TransformFinalBlock(encrypt_data, 0, encrypt_data.Length);
            }
            finally
            {
            //to clear the allocated memory
            desalg.Clear();
            md5.Clear();
            }
            //to convert to 64 bit string from converted md5 algorithm binary code
            return Convert.ToBase64String(results);
            }
           
           
         public string decrypt(string message)
        {
            byte[] results;
            string passphrase = "Password123";
            UTF8Encoding utf8 = new UTF8Encoding();
            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            byte[] deskey = md5.ComputeHash(utf8.GetBytes(passphrase));
            TripleDESCryptoServiceProvider desalg = new TripleDESCryptoServiceProvider();
            desalg.Key = deskey;
            desalg.Mode = CipherMode.ECB;
            desalg.Padding = PaddingMode.PKCS7;
            byte[] decrypt_data = Convert.FromBase64String(message);
            try
            {
                //To transform the utf binary code to md5 decrypt
                ICryptoTransform decryptor = desalg.CreateDecryptor();
                results = decryptor.TransformFinalBlock(decrypt_data, 0, decrypt_data.Length);
            }
            finally
            {
                desalg.Clear();
                md5.Clear();

            }
            //TO convert decrypted binery code to string
            return utf8.GetString(results);
        }