nPhase 3: C communicates with S
6.S decrypts the ticket to obtain the KC,S and
replies
to C with proof of possession of the shared secret (optional step)
nS è C: {timestamp, opt. subkey}Kc,s
n Notice that S
had to decrypt the authenticator, extract the timestamp & opt. subkey, and
re-encrypt those two components with Kc,s