using System;

using System.Text;

using System.Web;

using System.Security.Cryptography;

public class Program

{

​

    // url encode the base64 representation of the hashvar encodedSignatureHash = HttpUtility.UrlEncode(hashedBase64Value); private static string ComputeHMACSHA256Hash(string message, string secret) { // convert value to hash into a byte arrayvar encoding = new ASCIIEncoding();    

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var contractKey = "Y2eGoD5EgKDlPuCDoUQJ";

        var valueToHash = "3396603411.91202208035895254075069fedef401-5250-480d-997d-d8e566fb352c"; 

        var hashedBase64Value = ComputeHMACSHA256Hash(valueToHash, contractKey);

​

        Console.WriteLine(hashedBase64Value);

    }

    private static string ComputeHMACSHA256Hash(string message, string secret) { 

    var encoding = new ASCIIEncoding(); 

        var keyByte = encoding.GetBytes(secret);

        var messageBytes = encoding.GetBytes(message);

        using (var hmac = new HMACSHA256(keyByte))

        {

            var hashMessage = hmac.ComputeHash(messageBytes);  

            return Convert.ToBase64String(hashMessage);

        }

    }

}