Using identity, does anyone have sample code for creating my own dll to have single sign on (SSO) like twitter and facebook

Using identity, the following is in the startup.auth.cs file to use SSO for twitter, Facebook, etc.   How do i create my own for my own domains so they have single sign on across them.  There is a dll in bin that is the key. Any sample to create your own?

app.UseTwoFactorRememberBrowserCookie(DefaultAuthenticationTypes.TwoFactorRememberBrowserCookie);

            // Uncomment the following lines to enable logging in with third party login providers
            //  app.UseMicrosoftAccountAuthentication(
            //    clientId: "",
            //   clientSecret: "");

            //app.UseTwitterAuthentication(
            //   consumerKey: "",
            //   consumerSecret: "");

            //app.UseFacebookAuthentication(
            //   appId: "",
            //   appSecret: "");

            //app.UseGoogleAuthentication(new GoogleOAuth2AuthenticationOptions()
            //{
            //    ClientId = "",
            //    ClientSecret = ""
            //});