Re: [TLS] HKDF

Nikos Mavrogiannopoulos <nmav@redhat.com> Wed, 25 March 2015 15:36 UTC

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From: Nikos Mavrogiannopoulos <nmav@redhat.com>
To: Hugo Krawczyk <hugo@ee.technion.ac.il>
Date: Wed, 25 Mar 2015 16:36:16 +0100
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Subject: Re: [TLS] HKDF
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On Wed, 2015-03-25 at 11:21 -0400, Hugo Krawczyk wrote:


>         One idea for meaningful reduction of complexity in TLS is if
>         we could switch to cipher-based KDF. 
> ‚ÄčThat's for the WG to decide but the results we have for the
> extraction properties of block-cipher based PRFs are much weaker.

I'm not sure whether the WG should even decide on replacing the KDF or
the main protocols used. That was certainly a non-goal for TLS 1.3 and
is a cryptographic decision which is not the expertise of this group.
For such decisions, and even simpler (see Salsa20, ChaCha cipher
addition) this working group delegated these decisions to CFRG, and I
believe this should also be done now if we go the path of replacing
core TLS structure.

regards,
Nikos