I've got a simple client-server application based on TcpClient/TcpListener and SslStream. Clients can authenticate themselves to the server using a X509Certificate or by sending a user name and password after the SslStream has been established.
WCF makes use of the System.IdentityModel namespace for authentication purposes, but apparently that can be used in arbitrary applications--which sounds interesting. Information on how to do this is sparse though (or my Google foo is weak today).
So, my question is: What do I need to do to integrate System.IdentityModel with my application? I'm not sure if I need all that ClaimSet stuff, but it would be nice if users could log in just using their Windows account or any other provided authentication mechanism. (Unfortunately I can't just switch to WCF but have to use the custom protocol, although I can make some changes to it if necessary.)