sources.cs

// Startup.cs  
  public class Startup {
        public void ConfigureServices(IServiceCollection services) {
            services.AddGrpc();
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            app.UseRouting();
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapGrpcService<GreeterService>();
            });
        }
    }

// Program.cs
    public class Program
    {
        public static void Main(string[] args) {
            CreateHostBuilder(args).Build().Run();
        }
        public static X509Certificate2 GetCert() {
             // Retrieve a cert from the local windows store
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.ConfigureKestrel(options =>
                    {
                        options.ListenAnyIP(50052, o => {
                            var cert = Program.GetCert();
                            o.UseHttps(cert);
                            o.Protocols = HttpProtocols.Http2;
                        });
                    });
                    webBuilder.UseStartup<Startup>();
                });
    }