Windows Identity Foundation (WIF) enables .NET developers to externalize identity logic from their application, improving developer productivity, enhancing application security, and enabling interoperability. It is a framework for implementing claims-based identity in your applications. With WIF one can create more secure applications by reducing custom implementations and using a single simplified identity model based on claims.

Windows Identity Foundation is part of Microsoft's identity and access management solution built on Active Directory that also includes:

· Active Directory Federation Services 2.0 (formerly known as "Geneva" Server): a security token service for IT that issues and transforms claims and other tokens, manages user access and enables federation and access management for simplified single sign-on

· Windows CardSpace 2.0 (formerly known as Windows CardSpace "Geneva"): for helping users navigate access decisions and developers to build customer authentication experiences for users.

Reference : http://msdn.microsoft.com/en-us/security/aa570351.aspx

Geeta