This System.Security.Principal.IIdentity instance provides information to the FormsAuthenticationModule about the current user identity. This information consists of the username (Name), the type of authentication (AuthenticationType), which will always be "Forms," and the corresponding ticket object (Ticket)

public sealed class FormsIdentity : System.Security.Principal.IIdentity {
// Public Constructors
   public FormsIdentity(FormsAuthenticationTicket ticket);
// Public Instance Properties
   public string AuthenticationType{get; }          // implements System.Security.Principal.IIdentity
   public bool IsAuthenticated{get; }               // implements System.Security.Principal.IIdentity
   public string Name{get; }                        // implements System.Security.Principal.IIdentity
   public FormsAuthenticationTicket Ticket{get; }
}