Re: [TLS] DSA should die

Nico Williams <nico@cryptonector.com> Thu, 02 April 2015 01:38 UTC

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Date: Wed, 1 Apr 2015 20:38:49 -0500
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From: Nico Williams <nico@cryptonector.com>
To: Dave Garrett <davemgarrett@gmail.com>
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Subject: Re: [TLS] DSA should die
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On Wed, Apr 1, 2015 at 8:15 PM, Dave Garrett <davemgarrett@gmail.com> wrote:
> On Wednesday, April 01, 2015 08:48:36 pm Nico Williams wrote:
>> It would be better to also negotiate (cipher+mode), (hash), (KDF), and
>> (key agreement+server authentication) separately.
>
> I'm definitely in favor of reducing the combinatorial explosion in suites and moving hash, KEA, & etc. into a separate negotiation. Instead of an extension, you could just do the same thing again, really. Reserve a sizable block of the 16-bit suite space for hashes and another for KEA and list them all in the same cipher_suites array. TLS1 would ignore them, and TLS2 would just see points between [a,b] are hash, [b+1,c] are KEA, etc. So, new registries in the existing space, just dumped all into the same pile.

Yes, we could patch in a-la-carte ciphersuite negotiation by having
non-functional ciphersuites that wild-card all but the one kind of
thing.  You offer those.  A matching functional ciphersuite gets
selected.  Done.

TLS_*_*_WITH_AES_GCM_*
TLS_*_*_WITH_*_*_SHA384
TLS_ECDHE_*_WITH_*_*_*
...

Nico
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