[cryptography] open letter to Phil Zimmermann and Jon Callas of Silent Circle, re: Silent Mail shutdown
iang at iang.org
Sat Aug 17 05:41:39 EDT 2013
On 17/08/13 00:46 AM, Zooko Wilcox-OHearn wrote:
> We're trying an approach to this problem, here at LeastAuthority.com,
> of “*verifiable* end-to-end security”. For our data backup and storage
> service, all of the software is Free and Open Source, and it is
> distributed through channels which are out of our direct control, such
> as Debian and Ubuntu. Of course this approach is not perfectly secure
> — it doesn't guarantee that a state-level actor cannot backdoor our
> customers. But it does guarantee that *we* cannot backdoor our
Other than the open source solution , how does one do it? The
example of Skype and its self-immolated reputation for security is
In order to gain early credibility for its closed source solution, it
commissioned an audit of the tech. This audit gave it a good passing
grade, and specifically indicated that there were no known weaknesses,
and the claims were good. The aggressive cryptographic community was
However, an audit is a point-in-time review. That means it is only true
for that period of review. Auditors will specifically state that you
cannot rely on this review for a prediction of the future. The audit
must be repeated at some sort of regular interval to stop the company
changing its mind. The audit process must be a commitment to
continuation, so as to control that possibility.
In contrast, the public widely believes that an audit is a prediction of
the future (and the audit _profession_ does nothing to dissuade that
view). So Skype left that audit sitting there, and decided itself never
to repeat that audit . Fast forward nearly a decade, and the house
of cards came tumbling down: first the Heise discovery (as confirmed by
Adam Back here) and then the PRISM claims .
So back to Silent Circle. One known way to achieve some control over
their closed source replacement vulnerability is to let an auditor into
their inner circle, so to speak.
But if they wish to do this, they should not repeat the Skype mistake.
Especially as this is the known & routine PLC of a cryptographic tool:
first gain the trust of the cypherpunks, and promise them the world.
Then, when sale time comes, gain the trust of the NSA, and the promise
of future business.
 Remember that PGP Inc also tried the open source way. In the long
run, it didn't help. If you compare on brutal measures, Skype succeeded
with closed source, PGP Inc failed with open source. Of course it is
more complicated than that, but the end-delivery of security is
something that can be measured and can be relied upon.
 Nor to ever mention it, as rumour has it. As time went on, the
audit became more and more of an embarrassment...
 Rumour/hearsay confirms: Skype put the bad stuff in after the eBay
sale, and before the Microsoft sale (who for their sins were happy
either way). Up until around that time, the various European agencies
were lividly trying to gain access, and agitating in the press. We know
they got attack kits, and they also went quiet around the same time:
It's been a long time since a western TLA has complained about Skype --
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