Windows Identity Foundation
Windows Identity Foundation is a set of .NET Framework classes for implementing claims-based identity in your applications. By using it, you’ll more easily reap the benefits of claims-aware applications and services. It can be used in any Web application or Web service that uses the .NET Framework version 4.5 or later. WIF is just one part of Microsoft’s Federated Identity software family that implements the shared industry vision based on open standards. The other Federated Identity components include Active Directory® Federation Services (AD FS) 2.0, Windows Azure Access Control Services (ACS).