using System;

using System.Text;

using System.Security.Cryptography;

​

class Program

{

    public delegate double rectangleDelegate(double Width, double Heigth);

    class Rectangle

    {

        public double GetPerimeter(double Width, double Heigth)

        {

            return 2 * (Width + Heigth);

        }

​

        public double GetArea(double Width, double Heigth)

        {

            return Width * Heigth;

        }

    }

​

    static void Main(string[] args)

    {

        string tokenKey = "e1uTy+/blki9cNQPblQMBQ==";

        byte[] tokenKeyBinary = Convert.FromBase64String(tokenKey);

        using var hmac = new HMACSHA256(tokenKeyBinary);

        var hash = hmac.ComputeHash( System.Text.Encoding.UTF8.GetBytes(@"{""siteId"":""NOOlxt3rRruQuEciW6DyCg"",""type"":""HEARTBEAT"",""time"":""2023-11-04T09:08:03.539Z""}"));

        var hashInBase64 = Convert.ToBase64String(hash);

        hashInBase64.Dump();

    }

}