You might be interested in this set of videos[1] of public testimony by WhatsApp's Deputy General Counsel at a hearing on cybercrime in Brazil in December 2015, where he explains in some detail the type of information they have and don't have. He explicitly notes that they are incapable of accessing message content for end-to-end encrypted messages, and also explains that they don't retain copies of any communications once they've been delivered to recipients.

[1] http://www2.camara.leg.br/atividade-legislativa/comissoes/co...

I think that only messages sent between two android devices are encrypted using E2E. If you send a message to your mom (who uses a blackberry), the message won't be encrypted with that protocol.

What about ios? And how does your device know whether to encrypt or not? It's useless talking about encryption if the code is hidden. What if tomorrow they turn off the encryption silently?

They can turn off the encryption silently whether or not the code is hidden.

How so? You can compile yourself if you like.

More importantly, you could change the client to show encryption status before a message is sent and add client-side key management.

Sorry, I meant for the pre-compiled versions on Google Play and the App Store. The vast, vast majority of Whatsapp users aren't going to want to or don't know how to compile the app for their phone.

It's easier to say "no" to Brazil.

If they're partnered with Open Whisper Systems, it sounds like they're serious about end-to-end encryption.

They still keep a copy of all client encryption keys. :\

They have to. A phone number is not a key, so there's no way to avoid that.

However I've seen leaked screenshots that suggest at least the Android client is getting the ability to see what the keys are and pin them. Hence, TOFU encryption. It's about the best you can do in a consumer product.