Re: [openpgp] Deprecating SHA1

Peter Gutmann <pgut001@cs.auckland.ac.nz> Sun, 25 October 2020 05:58 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Jon Callas <joncallas=40icloud.com@dmarc.ietf.org>, "openpgp@ietf.org" <openpgp@ietf.org>
CC: Jon Callas <joncallas@icloud.com>
Thread-Topic: [openpgp] Deprecating SHA1
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Date: Sun, 25 Oct 2020 05:58:14 +0000
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Subject: Re: [openpgp] Deprecating SHA1
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Jon Callas <joncallas=40icloud.com@dmarc.ietf.org> writes:

>Here are a number of options possible.

Another thing to consider is how to deal with existing signed data.  If
there's a file that's been sitting on a local disk for twenty years signed
with SHA-1 then the signature isn't going to be suddenly invalid just because
SHA-1 is wobbly.  So some provision for recognising existing data as still
valid rather than "anything signed with SHA-1 is automatically suspect" would
be good.

Peter.