Re: [TLS] SHA-3 in SignatureScheme

Eric Rescorla <ekr@rtfm.com> Fri, 02 September 2016 17:06 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Fri, 2 Sep 2016 10:05:45 -0700
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To: Dave Garrett <davemgarrett@gmail.com>
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Subject: Re: [TLS] SHA-3 in SignatureScheme
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On Fri, Sep 2, 2016 at 10:04 AM, Eric Rescorla <ekr@rtfm.com> wrote:

>
>
> On Fri, Sep 2, 2016 at 8:25 AM, Dave Garrett <davemgarrett@gmail.com>
> wrote:
>
>> On Friday, September 02, 2016 07:32:06 am Eric Rescorla wrote:
>> > On Fri, Sep 2, 2016 at 3:42 AM, Ilari Liusvaara <
>> ilariliusvaara@welho.com> wrote:
>> > > I also don't see why this should be in TLS 1.3 spec, instead of being
>> > > its own spec (I looked up how much process BS it would be to get the
>> > > needed registrations: informative RFC would do).
>> >
>> > I also am not following why we need to do this now. The reason we
>> defined SHA-2 in
>> > a new RFC was because (a) SHA-1 was looking weak and (b) we had to make
>> significant
>> > changes to TLS to allow the use of SHA-2. This does not seem to be that
>> case.
>>
>> I don't think we strictly _need_ to do this now, however I think it's a
>> good idea given that we'll need to do it eventually
>
>
> I'm not sure that that's true.
>

To clarify: we might need to do this for one of several reasons:

- Some sort of completeness theory
- SHA-256 starts to look much weaker

The second could certainly happen, but if it doesn't, it's not clear that
there's really a completeness need.

-Ekr


>
> -Ekr
>
>