[295] in Kerberos
timestamps revisited
daemon@TELECOM.MIT.EDU (steiner@ATHENA.MIT.EDU)
Mon Dec 21 10:45:30 1987
From: steiner@ATHENA.MIT.EDU
To: kerberos@ATHENA.MIT.EDU
According to Steve's mail about timestamps, there are
two timestamps sent back to the client from the authentication
server: one is a copy of the client's original timestamp, sent
in the clear; the other is the Kerberos timestamp, sent back to
the client encrypted in the client's private key.
In that case, the Technical Plan is misleading. It says
... Anyone could send such a message or intercept its
response; that response, however, is usable only to the client named in
the original request, because Kerberos seals the response by
enciphering it in the private key of that client. The response contains
three parts: the ticket (which itself is further sealed in the private
key of the service), a newly-minted key for use in this client-server
session, and a copy of the timestamp that was in the original request.
I've modified it to read:
... Anyone could send such a message or intercept its
response; that response, however, is usable only to the client named in
the original request, because Kerberos seals the response by
enciphering it in the private key of that client. The response contains
three parts: the ticket (which itself is further sealed in the private
key of the service), a newly-minted key for use in this client-server
session, and the time of day according to the Kerberos server. A copy
of the client's original timestamp is returned in the clear, as a
bookkeeping aid to the client.
Jennifer
