using System;

using System.Security.Cryptography;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        var apiKey = Guid.Parse("0bc4a8e3459a43fc945477c2c36901a5");

        var connectionId = Guid.Parse("9e8111237a744e68bbdd27136968c51f");

        HMACSHA1 hmac = new HMACSHA1(UTF8Encoding.UTF8.GetBytes(apiKey.ToString("N").ToLower()));

        string authentication = Convert.ToBase64String(hmac.ComputeHash(UTF8Encoding.UTF8.GetBytes(connectionId.ToString("N").ToLower())));

        Console.WriteLine(authentication);

    }

}