[messaging] WhatsApp & OWS team up

[Tom Ritter]

On 19 November 2014 04:51, Mike Hearn <mike at plan99.net> wrote:
> However, the mathematics is not the hard part of this (assuming the code I
> have works). The hard part is designing the contracts between the different
> auditing companies to be watertight, so the developers of an app that is
> being threshold signed feel safe that they aren't going to lose control over
> their own product except in the very specific area of security guarantees.
> For example would those contracts govern UI changes that the auditors feel
> might make the security harder to understand? Very tricky area and never
> been done before so there are no templates to copy. Whoever goes first will
> be cutting a path through the jungle for everyone else.

Don't make it auditing companies, make it escrow companies.  Software
Escrow is apparently a pretty big business.  (My parent company NCC
does a lot of it.)  I'm not super knowledgeable about it, but the
idea, AFAICT, is BigCorp wants to buy a product from LittleCo but
worries about them disappearing.  LittleCo escrows the code with
EscrowLtd and everyone signs contracts saying EscrowLtd delivers the
code to BigCorp if certain conditions are met (LittleCo disappears,
75% development turnover, I have no idea).

Alter the contract so EscrowLtd produces a (reproducible) build of the
software you provide them and threshold signs it.  This should be
relatively easy if you're willing to provide them the software,
instructions on how to do it, and lots of money.

Then, and here's the trickiest part because we've (NCC) never done it
as far as I know, but I'm not opposed to it.  Have us, AuditCo, get
the software from EscrowLtd, and produce... something: a public
statement (we call the Independent Security Reports (ISRs), and there
are a few public ones) maybe even a full public report (we have a few
of those as well).

There's no dancing back and forth over whether we should or should not
make the threshold RSA signature.  I would _not_ be comfortable
signing any contract about that.  We get uncomfortable enough around
ISRs, and that contract very explicitly states we will write whatever
we damn well please.  But the audit company produces a document it's
satisfied with and the escrow company asserts that the thing built is
what you gave them and what the auditor audited.  So everyone's silo
is satisfied.

It's a complex system of third party trust... but so's yours.  And
mine has the advantage that we'd actually negotiate it with you and
sign paperwork. :)

-tom