I thought we were worried about collision of key *identifiers*, which were not necessarily raw keys or hashes thereof. But it's possible I was not paying enough attention and got confused.
-Ben On Tue, Jun 26, 2018 at 03:12:52PM +0000, Hannes Tschofenig wrote: > It does answer my question, Ben. > > This begs the question why the collision of session keys is suddenly a > problem in the ACE context when it wasn't a problem so far. Something must > have changed. > > Ciao > Hannes > > > -----Original Message----- > From: Benjamin Kaduk [mailto:ka...@mit.edu] > Sent: 26 June 2018 17:00 > To: Hannes Tschofenig > Cc: Mike Jones; Jim Schaad; draft-ietf-ace-cwt-proof-of-possess...@ietf.org; > ace@ietf.org > Subject: Re: [Ace] Key IDs ... RE: WGLC on > draft-ietf-ace-cwt-proof-of-possession-02 > > On Tue, Jun 26, 2018 at 08:53:57AM +0000, Hannes Tschofenig wrote: > > Ben, > > > > I was wondering whether the situation is any different in Kerberos. If the > > KDC creates tickets with a session key included then it needs to make sure > > that it does not create the same symmetric key for different usages. > > The key in the Kerberos ticket is similar to the PoP key in our discussion. > > > > Are we aware of key collision in Kerberos? > > I don't believe key collision is an issue in Kerberos. Long-term keys > (which are not what we're talking about here) are identified by a principal > name, encryption type, and version number. Session keys that are contained > within tickets (and returned to the client in the KDC-REP) are random, so > even if we are only using the birthday bound we're still in pretty good > shape. The modern enctypes tend to use subsession keys generated by the > client and/or server as well as the KDC-generated session key, which > provides further binding to the current session. > > Does that answer your question? > > -Ben > IMPORTANT NOTICE: The contents of this email and any attachments are > confidential and may also be privileged. If you are not the intended > recipient, please notify the sender immediately and do not disclose the > contents to any other person, use it for any purpose, or store or copy the > information in any medium. Thank you. _______________________________________________ Ace mailing list Ace@ietf.org https://www.ietf.org/mailman/listinfo/ace
