Re: [openpgp] v5 in the crypto-refresh draft

Peter Gutmann <pgut001@cs.auckland.ac.nz> Thu, 10 June 2021 05:40 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Daniel Kahn Gillmor <dkg@fifthhorseman.net>, Paul Wouters <paul@nohats.ca>
CC: "openpgp@ietf.org" <openpgp@ietf.org>
Thread-Topic: [openpgp] v5 in the crypto-refresh draft
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Date: Thu, 10 Jun 2021 05:40:34 +0000
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Subject: Re: [openpgp] v5 in the crypto-refresh draft
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Daniel Kahn Gillmor writes:

>Key ID or fingerprint comparison has been recommended in the past by the
>OpenPGP community as a reasonable way that one communications peer can
>confirm that they have the "right key".

Ah, good point, so it's a human-factors thing rather than just (say) mapping 
a signature to the key that signed it, where even if you can create a 
collision to point to a different key the signature check will still fail.

>which i'll call the "comparison-verification" practice:

Is it worth mentioning this in the text?  The current text just says "this 
thing is the fingerprint" with an implicit use elsewhere in the doc of
"the thing used to identify which key is being used", without mentioning its 
second, non-protocol use, to verify someone's key.

(Is this still done?  When was the last time someone here attended a key 
signing party?).

>I'm fine with either of these two framings, with a slight preference for
>Paul's text as it captures a bit more of the shifting landscape.

I'm happy with Paul's text as well.

Peter.