using System;

using System.Security.Cryptography;

using System.Text;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        string salt, sessionId, date, lang, theme, fullscreen;

        salt= "salt";

        sessionId="0";

        date= DateTime.UtcNow.ToString("u");;

        lang= "ar";

        theme= "light";

        fullscreen= "1";

​

​

        const string PublicKey = "OCWBZJHuWxyfENrjy6lE";

        const string PrivateKey = "9EgfDoaTcAshEaOWEy6p";       

        var message = date + lang + theme + fullscreen + sessionId + salt;

        var theDigest = CalculateDigest(PublicKey, PrivateKey, message);

        Console.WriteLine(theDigest);

        Console.WriteLine(date);

        Console.WriteLine("https://enrichment.tpay.me/headerenrichment/script-staging?salt="+salt+"&sessionId="+sessionId+"&date="+date+"&lang="+lang+"&theme="+theme+"&fullscreen="+fullscreen+"&digest="+theDigest);

    }

    public static string CalculateDigest(string publicKey, string privateKey, string message)

    {

        var digest = "";

        using (var hash = new HMACSHA256(Encoding.UTF8.GetBytes(privateKey)))

        {

            digest = publicKey + ":" + string.Join("", hash.ComputeHash(Encoding.UTF8.GetBytes(message)).Select(b => b.ToString("x2")));

        }

        return digest;

    }

}

//https://enrichment.tpay.me/headerenrichment/script?salt=salt&sessionId=0&date=2018-10-17 10:45:22Z&lang=ar&theme=light&fullscreen=1&digest=OCWBZJHuWxyfENrjy6lE:da01ef8ad2f708174ded3f99535640a376eb601212e7b8ed9b4c8e8af0df14ec