Re: [openpgp] New fingerprint: which hash algo
Daniel Kahn Gillmor <dkg@fifthhorseman.net> Fri, 23 October 2015 20:16 UTC
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From: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
To: Phillip Hallam-Baker <phill@hallambaker.com>, "Daniel A. Nagy" <nagydani@epointsystem.org>
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References: <878u84zy4r.fsf@vigenere.g10code.de> <55FD7CF0.8030200@iang.org> <87io742kz7.fsf@latte.josefsson.org> <87mvw4ctv5.fsf_-_@vigenere.g10code.de> <CA+cU71n1OUq4TtmY+8S2yfu2bvjAr+=DwtN-4xRW4xitjDpFXg@mail.gmail.com> <20151006110330.38b38ea4@latte.josefsson.org> <5616F2AE.5050106@iang.org> <561BAB91.8040104@epointsystem.org> <CAMm+LwjtzNzq-B78XwGoXFBRyJT4_6ZE0_-fojbw7=gbR9yvJw@mail.gmail.com>
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Date: Fri, 23 Oct 2015 16:16:10 -0400
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Subject: Re: [openpgp] New fingerprint: which hash algo
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On Fri 2015-10-23 14:00:56 -0400, Phillip Hallam-Baker wrote: > Due to the way OpenPGP works, it is not possible to have a recommended > algorithm for fingerprints. Every client has to be able to process any > recommended algorithm, so recommended means 'mandatory to accept'. But > there should definitely be two algorithms to choose from. In earlier discussions, i think people have made pretty convincing arguments that "two algorithms to choose from" is not a useful arrangement for OpenPGP fingerprints. In particular, fingerprints are used in verification contexts where the user has a bit of paper and sees something on the screen and is asked a question "do these things match?" If there are two algorithms to choose from, there are potentially two fingerprints to choose from, and this process becomes more complicated. the tool now has to either (a) first, ask the user which form of fingerprint is on the bit of paper before displaying the fingerprint (making fingerprint comparison a multi-roundtrip operation), or (b) present both and hope the user knows to ignore one or the other (similarly to how web browser certificate dialogs look, and we know how well that works). Either of these outcomes make this particular use case -- which already has bad usability -- worse. Arguably, we shouldn't encourage this use case at all, and should replace it with something like "type in the expected fingerprint and we'll tell you if it matches". If we make that decision, the argument for multiple fingerprint algorithms might be OK. But while i use this workflow myself, i think most users would find it too burdensome. Reading high-entropy hexadecimal (or base64 or whatever) is bad enough. typing it in is even worse. --dkg
- [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 vedaal
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 ianG
- Re: [openpgp] New fingerprint: to v5 or not to v5 Simon Josefsson
- Re: [openpgp] New fingerprint: to v5 or not to v5 Daniel Kahn Gillmor
- Re: [openpgp] New fingerprint: to v5 or not to v5 ianG
- Re: [openpgp] New fingerprint: to v5 or not to v5 Daniel A. Nagy
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: which hash algo (w… Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 Watson Ladd
- Re: [openpgp] New fingerprint: to v5 or not to v5 Phillip Hallam-Baker
- Re: [openpgp] New fingerprint: which hash algo (w… Tom Ritter
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 Mark D. Baushke
- Re: [openpgp] New fingerprint: to v5 or not to v5 Peter Gutmann
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 Peter Gutmann
- Re: [openpgp] New fingerprint: to v5 or not to v5 ianG
- Re: [openpgp] New fingerprint: to v5 or not to v5 ianG
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: which hash algo (w… Simon Josefsson
- Re: [openpgp] New fingerprint: to v5 or not to v5 Peter Gutmann
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 Peter Gutmann
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 Peter Gutmann
- Re: [openpgp] New fingerprint: which hash algo ianG
- Re: [openpgp] New fingerprint: which hash algo vedaal
- Re: [openpgp] New fingerprint: which hash algo Steve Pointer
- Re: [openpgp] New fingerprint: which hash algo Alessandro Barenghi
- Re: [openpgp] New fingerprint: which hash algo Robert J. Hansen
- Re: [openpgp] New fingerprint: to v5 or not to v5 Daniel Kahn Gillmor
- Re: [openpgp] New fingerprint: to v5 or not to v5 Peter Gutmann
- Re: [openpgp] New fingerprint: to v5 or not to v5 Jonathan McDowell
- Re: [openpgp] New fingerprint: to v5 or not to v5 Nicholas Cole
- Re: [openpgp] New fingerprint: to v5 or not to v5 Vincent Breitmoser
- Re: [openpgp] New fingerprint: which hash algo Daniel A. Nagy
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: to v5 or not to v5 Peter Gutmann
- Re: [openpgp] New fingerprint: to v5 or not to v5 Watson Ladd
- Re: [openpgp] New fingerprint: to v5 or not to v5 Werner Koch
- Re: [openpgp] New fingerprint: which hash algo Phillip Hallam-Baker
- Re: [openpgp] New fingerprint: which hash algo ianG
- Re: [openpgp] New fingerprint: which hash algo Daniel Kahn Gillmor
- Re: [openpgp] New fingerprint: which hash algo Phillip Hallam-Baker