DotNetOpenAuth - OpenID, OAuth, Infocard library for .NET

DotNetOpenAuth provides support for your site visitors to login with their OpenIDs by just dropping an ASP.NET control onto your page. It could be customized, how OpenID will operate on your site. It supports OpenID, OAuth and Infocards authentication. User registration and Signup of your site will be handled by this library. Users having Google, Twitter ID could login in to your site without having to create their own login.