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Re: [openpgp] SHA3 algorithm ids.

Peter Gutmann <pgut001@cs.auckland.ac.nz> Tue, 11 August 2015 13:21 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Phillip Hallam-Baker <phill@hallambaker.com>, Derek Atkins <derek@ihtfp.com>
Thread-Topic: [openpgp] SHA3 algorithm ids.
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Date: Tue, 11 Aug 2015 13:21:07 +0000
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Cc: IETF OpenPGP <openpgp@ietf.org>, ianG <iang@iang.org>
Subject: Re: [openpgp] SHA3 algorithm ids.
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Phillip Hallam-Baker <phill@hallambaker.com> writes:

>There is a very clear need for 512 bits and there is a case for 256 bits.

What's the clear need for -512?  By which I mean a demonstrated practical need
for a hash size of 64 bytes, not a hypothesised need given an imaginary
attack.  I can see a need for SHA-256 (to replace SHA-1), but for something
like SHA3-512 all I can see are downsides (compared to SHA2-256).

Peter.

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