Re: [openpgp] Fingerprint requirements for OpenPGP
Daniel Kahn Gillmor <dkg@fifthhorseman.net> Tue, 12 April 2016 14:32 UTC
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From: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
To: Vincent Breitmoser <look@my.amazin.horse>
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References: <87vb3nslqh.fsf@alice.fifthhorseman.net> <20160412083409.GA16775@littlepip.fritz.box>
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Date: Tue, 12 Apr 2016 10:32:47 -0400
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Cc: IETF OpenPGP <openpgp@ietf.org>
Subject: Re: [openpgp] Fingerprint requirements for OpenPGP
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On Tue 2016-04-12 04:34:09 -0400, Vincent Breitmoser wrote: >Daniel Kahn Gillmor(dkg@fifthhorseman.net)@Mon, Apr 11, 2016 at 08:40:22PM -0400: >> * it should be cheap to compute from a given key -- you shouldn't need >> a gig of RAM or a minute of CPU to calculate the fingerprints of any >> key. > > Strictly speaking, we can be slightly less restrictive: It must be > cheap to verify, given a fingerprint, that it's the correct one for a > key. This distinction does not make a difference unless we store the > fingerprints as part of the data format (which we probably shouldn't), > so this is more of an academic point. Right, i don't think we should store the fingerprint as part of the data format, so we still need to be able to rapidly generate it, not just verify it. >> * it should be strong enough that we do not believe anyone can create a >> key with a fingerprint that collides with another key's fingerprint > > Quite importantly, this should be "another *independent* key's > fingerprint", i.e. the requirement is preimage resistance, not > collision resistance. Creating two keys with colliding fingerprints > is fine, at least noone could come up with a attack scenario where it > mattered. This clarification also matches my understanding. Thanks for the precision, Vincent. --dkg
- [openpgp] Fingerprint requirements for OpenPGP Daniel Kahn Gillmor
- Re: [openpgp] Fingerprint requirements for OpenPGP Vincent Breitmoser
- Re: [openpgp] Fingerprint requirements for OpenPGP Joseph Lorenzo Hall
- Re: [openpgp] Fingerprint requirements for OpenPGP Vincent Breitmoser
- Re: [openpgp] Fingerprint requirements for OpenPGP Daniel Kahn Gillmor
- Re: [openpgp] Fingerprint requirements for OpenPGP Derek Atkins
- Re: [openpgp] Fingerprint requirements for OpenPGP Daniel Kahn Gillmor
- Re: [openpgp] Fingerprint requirements for OpenPGP Derek Atkins
- Re: [openpgp] Fingerprint requirements for OpenPGP Daniel Kahn Gillmor
- Re: [openpgp] Fingerprint requirements for OpenPGP Salz, Rich
- Re: [openpgp] Fingerprint requirements for OpenPGP Daniel Kahn Gillmor
- Re: [openpgp] Fingerprint requirements for OpenPGP Werner Koch
- Re: [openpgp] Fingerprint requirements for OpenPGP Werner Koch
- Re: [openpgp] Fingerprint requirements for OpenPGP KellerFuchs
- Re: [openpgp] Fingerprint requirements for OpenPGP Derek Atkins
- Re: [openpgp] Fingerprint requirements for OpenPGP Jon Callas
- [openpgp] proof-of-work fingerprints [was: Re: Fi… Daniel Kahn Gillmor
- Re: [openpgp] Fingerprint requirements for OpenPGP Daniel Kahn Gillmor
- Re: [openpgp] Fingerprint requirements for OpenPGP Werner Koch
- Re: [openpgp] Fingerprint requirements for OpenPGP Bill Frantz
- Re: [openpgp] Fingerprint requirements for OpenPGP Werner Koch
- Re: [openpgp] Fingerprint requirements for OpenPGP Derek Atkins
- Re: [openpgp] Fingerprint requirements for OpenPGP Derek Atkins
- Re: [openpgp] Fingerprint requirements for OpenPGP Derek Atkins
- Re: [openpgp] Fingerprint requirements for OpenPGP Derek Atkins
- Re: [openpgp] Fingerprint requirements for OpenPGP Joseph Lorenzo Hall
- Re: [openpgp] Fingerprint requirements for OpenPGP Werner Koch
- Re: [openpgp] Fingerprint requirements for OpenPGP Werner Koch
- Re: [openpgp] Fingerprint requirements for OpenPGP Vincent Breitmoser
- Re: [openpgp] Fingerprint requirements for OpenPGP Joseph Lorenzo Hall
- Re: [openpgp] Fingerprint requirements for OpenPGP Derek Atkins
- Re: [openpgp] Fingerprint requirements for OpenPGP Derek Atkins
- Re: [openpgp] Fingerprint requirements for OpenPGP Joseph Lorenzo Hall
- Re: [openpgp] Fingerprint requirements for OpenPGP Phillip Hallam-Baker
- Re: [openpgp] proof-of-work fingerprints [was: Re… Phillip Hallam-Baker
- Re: [openpgp] proof-of-work fingerprints [was: Re… Phillip Hallam-Baker