[Enigmail] Popescu and keys
Daniel Kahn Gillmor
dkg at fifthhorseman.net
Thu May 21 18:23:20 CEST 2015
On Wed 2015-05-20 20:13:32 -0400, Robert J. Hansen wrote:
> In the last couple of days a few different people have pointed me to
> Mircea Popescu's blog, where he's claimed he's broken ~150 keys that are
> in common circulation among the keyservers.
At least one of the keys he claimed to have broken is a degraded copy of
one of H. Peter Anvin's actual subkeys, as Hanno Böck pointed out here:
To my knowledge, Mircea (cc'ed here) has not retracted this particular
claim, despite having issued at least three updates to his initial
report about this key (which is not behind a paywall at the moment):
> Unfortunately, his blog post is rather difficult to read: it's full of
> rude political asides that have no bearing on anything cryptological.
> I regret that, because it obscures what I think is a fascinating
> question: has he actually managed to recover private keys given just
> the public key?
> He claims to already have broken my key. If so, proving it is
> straightforward: sign a 256-bit value with my private key and upload it
> somewhere the world can see it.
> I'm going to be fascinated by the results, one way or another. If he
> can successfully do this it's going to lead to a lot of very interesting
> For those people who are concerned about this, relax and remember to
> breathe. :)
> The 256-bit value, in base64 encoding:
> * anr8HIZZ1hRjeaXDxJ71qBNpw5s9r+42CqF+Bpk9vU4=
Which key does he claim to have broken? If Mircea has broken your
encryption-capable subkey (0xB8A6B74C001892C2) then he might only be
able to decrypt messages sent to you, but not sign them.
To provide him with an opportunity to demonstrate this (Hi Mircea!),
i've produced this message, encrypted to rjh's encryption-capable
Mircea, if you can decrypt it, you should find a secret message, signed
by me, which includes within it the message-id of the e-mail i'm
You can either produce the session-key (e.g. with gpg
--show-session-key) or produce the signed message to demonstrate that
you have control of Robert's secret key material:
-----BEGIN PGP MESSAGE-----
Version: GnuPG v2
-----END PGP MESSAGE-----
Given the poor communication patterns and lack of retraction of
unfounded claims, i'm not currently worried that this is a real attack.
I am prepared to take it seriously if Mircea can follow up effectively
on either of the challenges here, though.
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