title: How to implement active federation provider with WIF
body: <p>I have several Silverlight, WP7 and ASP.NET MVC client applications Most allow anonymous access to the application but secure various features based on a user's credentials when logged in.  All of the clients use a common back-end service application for data access and business processing which require the user's credentials for authentication and authorization.</p>
  
  <p>We currently use Forms Authentication in all client applications and I'd like to migrate our architecture to use federated identity and a claims-based model.  Passive federation is not an option.</p>
  
  <p>I am looking for the following flow:</p>
  
  <ol>
  <li>The user triggers the login dialog, enters their username and
  password then clicks "OK".</li>
  <li>Behind-the-scenes, the application calls an active STS service in
  our existing service application for authentication.</li>
  <li>The service is actually a federated STS and passes the call through
  to the (active) IP_STS which may or may not be ADFS.</li>
  <li>When the IP returns the token to the FP, the FP modifies the token
  with additional claims from the server data store before returning
  the token to the client application.</li>
  <li>The client application maintains the token in memory for
  authorization checks (in Thread.CurrentPrincipal, for example).</li>
  <li>The client also passes the token when making requests to other
  service operations in our service application.</li>
  <li>These service operations will use the token to
  authenticate/authorize the request.</li>
  </ol>
  
  <p>This is a very different use-case from any of the articles and samples I've been able to locate.  Can anyone provide some guidance and/or point me in the right direction?</p>