March 5, 2002
Practical Aspects of Modern Cryptography
15
The Basic Kerberos Protocol (3)
nPhase 2: C gets a Ticket for S
3.C requests a ticket to communicate with S from the ticket-granting service (TGS)
nC sends TGT to S along with an authenticator requesting a ticket from C to S
nC è  TGS: {AC,S}KC,TGS , {TC,TGS}KTGS
nwhere Ac,s = {c, timestamp, opt. subkey}Kc,s 
nFirst part proves to TGS that C knows the session key
nSecond part is the TGT C got from the KDC