This is continuation of my previous post Basic Authentication with ASP.NET Web API Using OWIN Middleware, where I implemented HTTP basic authentication in a custom OWIN middleware class AuthenticationMiddleware that derives from the OwinMiddleware class. However, when it comes to implementing authentication in an OWIN middleware, the recommended approach is to use the authentication micro-framework that Katana has and derive from the out-of-box middleware class AuthenticationMiddleware<T>. Of course, this special authentication middleware also derives from OwinMiddleware, like so.