Re: [openpgp] New fingerprint: to v5 or not to v5

Peter Gutmann <pgut001@cs.auckland.ac.nz> Sat, 10 October 2015 02:11 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Daniel Kahn Gillmor <dkg@fifthhorseman.net>, ianG <iang@iang.org>, "openpgp@ietf.org" <openpgp@ietf.org>
Thread-Topic: [openpgp] New fingerprint: to v5 or not to v5
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Date: Sat, 10 Oct 2015 02:11:42 +0000
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Subject: Re: [openpgp] New fingerprint: to v5 or not to v5
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Daniel Kahn Gillmor <dkg@fifthhorseman.net>; write:

>For X.509, we do have certificate fingerprints, but they turn out to not be
>particularly useful.

Actually they're very useful if you're doing proper checking in your PKI (so
not relying on commercial CAs or any of the X.500/X.509 folderol that doesn't
work), you either fingerprint the cert(s) you expect to see (e.g. for securing
a web service for a mobile app) or the CA cert that you rely on to issue certs
you can rely on. You can also use them for cute things like self-certifying
URLs, the first part of the FQDN is a hash of the cert at that location.

Peter.