From gnupg-users  Wed Mar 07 20:31:11 2012
From: Ingo =?utf-8?q?Kl=C3=B6cker?= <kloecker () kde ! org>
Date: Wed, 07 Mar 2012 20:31:11 +0000
To: gnupg-users
Subject: Re: invalid gpg key revocation
Message-Id: <201203072131.16722 () thufir ! ingo-kloecker ! de>
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On Tuesday 06 March 2012, Daniel Kahn Gillmor wrote:
> On 03/05/2012 04:36 PM, Ingo Kl=C3=B6cker wrote:
> > 4. He has left his laptop unlocked and unattended for a very short
> > period of time and he is using gpg-agent with a cache-ttl > 0.
> >=20
> > I have verified that one can generate a revocation certificate
> > without entering a passphrase if one has previously signed
> > something (e.g. an email). So, it was probably just a very nasty
> > prank.
>=20
> as pranks involving compromise of the secret key go, this is the
> least-nasty prank i can think of.
>=20
> > Maybe gpg shouldn't use the cached signing passphrase (or any
> > cached passphrase) for generating a revocation certificate.
>=20
> But it's ok to use the cached signing passphrase for making bogus
> identity certifications?
>
> For signing ersatz love letters?
>=20
> What's to stop the malefactor from just querying the passphrase
> directly out of gpg-agent and absconding with both it and the secret
> key material to do whatever they want later?
>=20
> I don't think making the proposed limitation is a helpful one.

Hmm. I guess you are right. Just a minor remark: To my knowledge it is=20
not possible to get the passphrase out of gpg-agent. The whole point of=20
gpg-agent is that it encapsulates all operations involving the secret=20
key and the passphrase in order to minimize the risk of leaks of this=20
information (see http://www.gnupg.org/aegypten/tech.en.html).


Regards,
Ingo

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