OWIN OAuth 2.0 Authorization Server
The OAuth 2.0 framework enables a third-party app to obtain limited access to an HTTP service. Instead of using the resource owner's credentials to access a protected resource, the client obtains an access token (which is a string denoting a specific scope, lifetime, and other access attributes). Access tokens are issued to third-party clients by an authorization server with the approval of the resource owner.
OWIN defines a standard interface between .NET web servers and web applications. The goal of the OWIN interface is to decouple server and application, encourage the development of simple modules for .NET web development, and, by being an open standard, stimulate the open source ecosystem of .NET web development tools.
For more information, see OWIN