Assembly: System.Web (in system.web.dll)
You must install the Passport SDK in order to use the.NET Passport classes and methods. Passport SDK version 1.4 is supported but not recommended. Passport SDK version 2.0 is both supported and recommended.
Only Passport SDK version 2.0 is supported under Windows XP.
The PassportAuthentication_OnAuthenticate event is raised for applications that are designed to attach a custom IPrincipal object to the context. The Passport service itself does the authentication, so that cannot be overridden.
|How to: Implement Passport Authentication in ASP.NET Applications||Building ASP .NET Web Applications|