Path: utzoo!attcan!uunet!clyde.concordia.ca!news-server.csri.toronto.edu!rutgers!uwm.edu!bionet!agate!shelby!ATHENA.MIT.EDU!wesommer
From: wesommer@ATHENA.MIT.EDU (Bill Sommerfeld)
Newsgroups: comp.protocols.kerberos
Subject: Re: Why is initial user authentication done the way it is?
Message-ID: <9006150126.AA22710@E40-008-10.MIT.EDU>
Date: 15 Jun 90 01:26:25 GMT
Sender: daemon@shelby.Stanford.EDU
Organization: The Internet
Lines: 16

Jon claims in his revised protocol that:

   there is no way to get an encrypted ticket to bang on without
   first proving to the server that you are who you claim to be.

Sure there is.  All I have to do is get a valid TGT, and then ask the
KDC for a ticket to jik@ATHENA.MIT.EDU.  The response will include a
"ticket to jik", which will contain my name (and other things)
encrypted in your key.  I can then bang on the ticket all I want in
the privacy of my own CPU.

Remember that in Kerberos there is no difference between users and
servers.

					- Bill