Verify SSL thumbprint

gistfile1.txt

using System;
using System.IO;
using System.Net;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.Security.Principal;

namespace SslTest
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            var url = new Uri("https://ssltest.dev/");

            var request = WebRequest.Create(url);
            request.Method = "GET";
            request.ImpersonationLevel = TokenImpersonationLevel.Anonymous;

            ServicePointManager.ServerCertificateValidationCallback += ServerCertificateValidationCallback;

            using (var response = request.GetResponse())
            using (var stream = response.GetResponseStream())
            using (var reader = new StreamReader(stream))
            {
                Console.WriteLine(reader.ReadToEnd());
            }

            Console.ReadKey();
        }

        private static bool ServerCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
        {
            const string expectedHash = "B5B99C4FEEF719A3A2B5D43EAD8677053A8847E2";

            if (errors != SslPolicyErrors.None)
                return false;

            var hash = certificate.GetCertHashString();
            if (!expectedHash.Equals(hash, StringComparison.Ordinal))
                return false;

            return true;
        }
    }
}