Re: [openpgp] Fingerprint requirements for OpenPGP

Joseph Lorenzo Hall <joe@cdt.org> Wed, 13 April 2016 15:24 UTC

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From: Joseph Lorenzo Hall <joe@cdt.org>
Date: Wed, 13 Apr 2016 11:23:44 -0400
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To: Vincent Breitmoser <look@my.amazin.horse>
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Subject: Re: [openpgp] Fingerprint requirements for OpenPGP
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On Tue, Apr 12, 2016 at 9:15 AM, Vincent Breitmoser
<look@my.amazin.horse> wrote:
> Joseph Lorenzo Hall(joe@cdt.org)@Tue, Apr 12, 2016 at 09:06:11AM -0400:
>> If you have two keys that map to the same fingerprint, then an
>> attacker can decide to serve you whichever is in their best interest.
>
> The premise of your scenario is that you are already using a key
> generated by the attacker. What could an attacker possibly gain by
> possessing a second key with the same fingerprint?

Sorry so slow to respond... my premise is that increasingly I query
for full fprs to obain keys from keyservers and if that maps onto two
different keys with the same UserID that would be bad.

I guess what the rest of the thread here is saying is that it would be
so computationally difficult for a malicious keyserver to find a
collision that this isn't a problem.

(apologies for being somewhat dense)

-- 
Joseph Lorenzo Hall
Chief Technologist, Center for Democracy & Technology [https://www.cdt.org]
e: joe@cdt.org, p: 202.407.8825, pgp: https://josephhall.org/gpg-key
Fingerprint: 3CA2 8D7B 9F6D DBD3 4B10  1607 5F86 6987 40A9 A871