Assembly: System.Web.Security.SingleSignOn (in system.web.security.singlesignon.dll)
The SingleSignOnIdentity object is set on the HttpContext for the Web application by the SingleSignOnAuthenticationModule. The Web forms then use the properties and methods from the SingleSignOnIdentity object to perform authentication and authorization tasks.
The SingleSignOnIdentity object is used by the ASP .NET Web application to get direct claim information about the authenticated client and to allow the application to control when redirects to the logon server occur. In addition, this object also has sign out methods.