An RDP profile can name a Kerberos KDC; CredSSP then authenticates with
Kerberos instead of NTLM, reaching the KDC through a small TCP client
(RFC 4120 length-prefixed framing, 5 s connect / 10 s read timeouts,
replies capped at 1 MiB so a hostile KDC can't force a huge allocation).
UDP KDCs are refused with a clear message. Tested against a fake KDC
(round trip, oversized reply, UDP); not against a real realm.
Smart-card logon is not implemented: it needs PC/SC hardware and a card
to build and test against.
Andy Dixon
455d8fa6da