Windows Identity Foundation

Windows Identity Foundation is a Framework developed by Microsoft to help applications/service to recognize and use Security Tokens based on claims. In short it enables Claim Based Authentication for Applications and Services.

WIF provides a set of APIs which the applications can make use of to recognize the details from the claims, it helps applications to make decisions on whether to Grant/Deny access to the user/service based on the details in the Claims.

WIF provides a utility FedUtil, which helps in establishing the Trust between applications and the Identity Provider (STS). 


Apart from helping applications to process claims, WIF also helps in creating a Identity Provider (STS) which can be used to validate users and provide security tokens to other applications / services.

To know more about Windows Identity Foundation (WIF) refer to Microsoft’s WIF page
http://msdn.microsoft.com/en-us/library/ee748475.aspx

The following code project article provides detailed information on how to set up an Identity Provider (STS) and use the same from an Asp.Net site using Windows Identity Foundation (WIF).
http://www.codeproject.com/Articles/278940/Claim-based-Authentication-and-WIF-Part-2