Re: [TLS] confirming the room’s consensus: adopt HKDF PRF for TLS 1.3

Sean Turner <turners@ieca.com> Wed, 01 April 2015 21:27 UTC

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From: Sean Turner <turners@ieca.com>
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Subject: Re: [TLS] =?windows-1252?q?confirming_the_room=92s__consensus=3A_adop?= =?windows-1252?q?t_HKDF_PRF_for_TLS_1=2E3?=
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On Apr 01, 2015, at 15:48, Ilari Liusvaara <ilari.liusvaara@elisanet.fi> wrote:

> On Wed, Apr 01, 2015 at 03:19:33PM -0400, Russ Housley wrote:
>> 
>> One detail that was not discussed because we were running out of
>> time is important to me (and may be important to others).  SHA-256
>> would be the MTI.  Is an alternative hash function chosen based on
>> the cipher suite or some other mechanism?

I’m sure you saw the other thread where we’re discussing MTI, but if not SHA-256 was the proposed MTI.

> In TLS 1.2 and 1.3-current, the main PRF-hash is designated by
> the ciphersuite. I have not seen any proposals to change this.

Yeah there’s been no propose to change this.  Granted @ the interim we did discuss hard coding SHA-256 but knowing there will be profiles that will want to use something else we decided hard coding it was not a great idea.

spt

> Then there is signature hash, which is negotiated using
> extensions.
> 
> 
> -Ilari
> 
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