/// <summary>Decodes the encrypted text using the Advanced Encryption Standard (AES) algorithm.</summary> 

        /// <param name="Id">The unique identifier.</param> 

        /// <param name="timestamp">The timestamp.</param> 

        /// <param name="secret">The secret. Must be a 24-character unsigned alphanumeric string.</param> 

        /// <param name="encryptedText">The text to decode.</param> 

        /// <returns>The decoded text.</returns> 

        internal static string Decrypt(Guid Id, DateTime timestamp, string secret, string encryptedText) 

        { 

            byte[] requestBytes = Id.ToByteArray(); 

            byte[] timestampBytes = BitConverter.GetBytes(timestamp.Ticks); 

            byte[] sharedSecretBytes = encoding.GetBytes(secret); 

            byte[] buffer = Convert.FromBase64String(encryptedText); 

  

            using (Aes aes = Aes.Create()) 

            { 

                aes.KeySize = 256; 

                aes.BlockSize = 128; 

                aes.Padding = PaddingMode.PKCS7; 

                aes.Mode = CipherMode.CBC; 

                aes.Key = timestampBytes.Concat(sharedSecretBytes).ToArray(); 

                aes.IV = requestBytes; 

  

                ICryptoTransform decryptor = aes.CreateDecryptor(); 

  

                return encoding.GetString(decryptor.TransformFinalBlock(buffer, 0, buffer.Length)); 

            } 

        }