On Fri, Nov 21, 2014 at 10:15 AM, Joseph Bonneau <[email protected]> wrote:
> > On Fri, Nov 21, 2014 at 10:06 AM, Nadim Kobeissi <[email protected]> > wrote: >> >> You can actually get around the need to trust WhatsApp as a centralized >> key directory (by implementing a simple form of key authentication (QR >> codes, fingerprints, etc.)), but that wouldn't solve the problem. The issue >> here is that even if key authentication is implemented, WhatsApp servers >> still retain the capacity to selectively disable encryption on a case by >> case basis. >> > > If you trust the app (verified build, etc.) then the app will tell you > you're communicating in non-encrypted mode. If you don't trust the app, > then the app can show you one fingerprint and encrypt with another (or not > at all), so independent verification of key fingerprints also won't help. > Except that even a deterministic build of the app right now wouldn't show you anything regarding encryption status! I do get your point. But the server having so much control, in my view, still interferes, even with deterministically-built clients, to a degree that definitely warrants it being its own "third challenge." It means that I can compile from source, authenticate, and still have my encryption quietly disabled when I fly to Thailand/Saudi Arabia. This is a third challenge that you can address with a combination of client-side checks and UI, but it still gives servers too much power. > > I should have said "assuming a trusted app and a means of independent key > verification" then the ability to disable encryption isn't any worse. So > we're back to the 2 main challenges either way. >
_______________________________________________ Messaging mailing list [email protected] https://moderncrypto.org/mailman/listinfo/messaging
