Re: [TLS] Negotiate only symmetric cipher via cipher suites (was: Ala Carte Cipher suites - was: DSA should die)

Dave Garrett <davemgarrett@gmail.com> Mon, 13 April 2015 16:00 UTC

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From: Dave Garrett <davemgarrett@gmail.com>
To: tls@ietf.org, Daniel Kahn Gillmor <dkg@fifthhorseman.net>
Date: Mon, 13 Apr 2015 12:00:00 -0400
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Subject: Re: [TLS] Negotiate only symmetric cipher via cipher suites (was: Ala Carte Cipher suites - was: DSA should die)
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On Monday, April 13, 2015 03:14:45 am Daniel Kahn Gillmor wrote:
> On Mon 2015-04-13 02:01:52 -0400, Dave Garrett wrote:
> > Assign points to NamedGroup and
> > SignatureAlgorithm to negotiate PSK usage via the
> > extensions. (e.g. NamedGroup=0 for plain PSK)
> 
> I'm not convinced that we want to use 0 for PSK (this may be purely
> aesthetic: it makes PSK sound like the "default", and if we later find
> other non-DH key exchange we want to stuff in this registry, it'd be
> nice to group them together, and there are no available neighbors close
> to 0).  I think i'd be ok using some other currently-unallocated
> codepoint, though.

The thought process was 0 for N/A in the case of PSK without (EC)DHE. I would much prefer that only (EC)DHE_PSK be permitted, which would make this a non-issue.


Dave