[680] in Kerberos
Re: Davis/Swick discussion
daemon@TELECOM.MIT.EDU (Steve Miller)
Wed Mar 29 17:55:07 1989
From: miller%erlang.DEC@DECWRL.DEC.COM (Steve Miller)
To: kerberos@ATHENA.MIT.EDU
I take issue with the statement by Don Davis and Ralph Swick that
"Currently, Kerberos supports only user-to-secure-host authentication."
This is incorrect. Kerberos supports principal-to-principal (e.g. user-to-user)
authentication. This is clearly demonstrated by observing that the protocols
always specify source and destination principal, that hosts may store multiple
server (destination principal) keys, and that one must
re-authenticate to communicate (via Kerberos) with additional principals
residing at the same host. In other words, it is not like logging in to
a local system, where you are normally performing user-host authentication,
and once successfully done, have been authenticated for *All* the services
local to the host. The current Kerberos implementation uses the host as
a secure repository of the set of server keys, however this is not
a requirement. For example, a host receiving a Kerberos mediated
request could present the encrypted ticket on the display (or an RS232 port),
where it would then be input to a smart card which would decrypt the
ticket using the *principal's* key.
My issue is with their description. Based on reading a previous draft,
I do believe that they are trying to address a legitimate problem, that is,
avoiding storing long-lived server master keys on hosts. I do not have
any comments yet on the current version.
Steve.
