Authorization in MVC with Authorization Filter is awesome thing. In MVC context controllers are all our resources for user more often i.e. users interact with our application using url and in MVC a url is mapped with our controllers and that's all.A controller is also consists of number of actions which are also used in url call.The point here is why not we should filter users requests to our resources and using a filter whole controller can be checked for a particular user (based on username, role or any thing ) as well as an individual action inside a controller.Asp.net MVC4 provides basic filters implementation in default template but we are going to do something different.
That is how we can use Authorization Filter to authorize users on the basis of their roles,names etc
I hope this little introduction helps for your further exploration.