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Re: [openpgp] New fingerprint: which hash algo (was: to v5 or not to v5)

Simon Josefsson <simon@josefsson.org> Tue, 06 October 2015 09:03 UTC

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Date: Tue, 06 Oct 2015 11:03:30 +0200
From: Simon Josefsson <simon@josefsson.org>
To: Tom Ritter <tom@ritter.vg>
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Cc: IETF OpenPGP <openpgp@ietf.org>, ianG <iang@iang.org>
Subject: Re: [openpgp] New fingerprint: which hash algo (was: to v5 or not to v5)
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> On 30 September 2015 at 01:18, Werner Koch <wk@gnupg.org> wrote:
> > On Mon, 21 Sep 2015 11:13, simon@josefsson.org said:
> >
> >> Regarding which hash to use, SHA-256 is probably the simplest
> >> choice From a practicallity and consensus point of view.  Are
> >> there any strong reasons to favor something else?
> 
> I have a small preference to see the fingerprint algorithm match what
> we believe the most popular signature (hash) algorithm will be. I've
> been working with a number of embedded folks and code size can often
> be a big concern. More Algorithms, More Code.

My perception is that the most popular signature hash algorithms right
now are SHA-256 and SHA-512.  While SHA-256 and SHA-512 have somewhat
different characteristics on different platforms, I believe we are
approaching the limit of where a lot of additional comparisons are
worth the time and effort compared to just pick one of them.  I'm fine
with SHA-256 for the reasons that Werner presented.  Does someone
else want to promote another option?  Can we get closure on this?

/Simon

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