Windows Identity Foundation (WIF) is a Microsoft software framework for building identity-aware applications.
[1] It provides APIs for building ASP.NET or WCF based security token services as well as tools for building claims-aware and federation capable applications.
[2][3] Windows Identity Foundation is supported on IIS 6/Windows Server 2003, IIS 7/Windows Vista, Windows Server 2008 and Windows 7.
Version 1.0 shipped as a standalone product, but the product is now included as a part of Microsoft .NET Framework v4.5.
[4][2] WIF has the following major features:[5]