I feel the same way. Just build an independent app already. Telegram did it well. What's stopping WhatsApp ?

Monetization strategy is what's stopping Whatsapp. Eventually, there will be an official API so business can hook CRMs to clients' Whatsapp accounts. However, FB is first trying that with Messenger API/bots. I assume Whatsapp API/bots comes next.

FB did not pay billions for the most popular chat app just to let 1 billion people use it for free forever...

Free? Every WhatsApp user paid Facebook on day one with the contents of their address book and how frequently one person contacts another. This is of huge value if your business model is exactly to gather this kind of data.

All the talk about encryption and privacy seems to ignore this basic point. Association can be dangerous and this does not protect people from exposing themselves in that way.

True, but to be honest I am not sure that alone is worth 22B, in particular when you have to show shareholders how you plan to make that money back.

http://www.bloomberg.com/news/articles/2014-10-28/facebook-s...

As kawera said two comments above yours:

Their servers do not store unencrypted messages so they need to come from the phone.

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That's why some people criticise Telegram: Their messages have to be stored unencrypted for their setup to work.

Exactly. Telegram's "Secret Conversations" are encrypted end-to-end but then they aren't synced (or even supported on desktop).

My workaround for this is to create a group chat. I only talk to two people on Signal but I've asked both of them to message in the group chat that I've made. Now, I can answer chat messages on my nexus 5, nexus 6, and nexus 7. (I built the apk from source for the Nexus 7. I wouldn't recommend this if you actually want secrecy. I'm not doing anything confidential so I am not too worried about targeted attempts.)

What's stopping them from either providing a way to sync the key to other devices, or allow the device to register its own keys, and they just store a couple copies of the encrypted data?

It seems like there should be ways to do it without storing unencrypted data.

AFAIK Apple Message implements encryption and has independent clients. So I think the problem can be solved with some effort.

Each device has its own key. Before a message is sent, the client grabs all the keys for each device associated with the account of the recipient, it then encrypts the message separately for each device and sends a separate encrypted copy for each device.

This scheme has various weaknesses, eg. a rogue key could be associated with someone's account without their knowledge, and anyone who sends this person messages will therefore be sending a copy encrypted with the rogue key.

Telegram also only shares unencrypted chats across multiple devices.

How could then sync end-to-end encrypted messages?

Sender encrypts same message several times, one for each receiver device.

Store them the same way they store today.

When the first device picks up the message, mark as delivered, when the user reads it, mark as read.

Something along those lines, I guess.

EDIT: message is encrypted, but not it's metadata, as the server must know where it came from and where it is going to.

Considering how much information about a subject is inferrable by means of metadata only, I'd say this is a much better solution, security wise.

Same way iMessage does

The same way Signal does is probably a better example.

Keep in mind that Whatsapp still supports pretty old devices (Nokia S40/60), where you may not want to encrypt every image N times.

Edit: remove some stuff.

Actually iMessage doesn't encrypt each image N times. It encrypts once, upload it to a server, then encrypts the image encryption key N times.

A possible procedure is described by Moxie here:

https://moderncrypto.org/mail-archive/messaging/2014/001022....