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WhatsApp's Signal Protocol integration is now complete

whispersystems.org

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Re: WhatsApp's Signal Protocol integration is now complete

#171
post #159
post #63

Earlier quoted context omitted.

Only if builds are fully reproducible, which is rarely true. Otherwise, the source can make it harder, by lying to you.

Then demand reproducible builds from software with security claims?

Can I have serious cryptanalytic audits first? Because virtually nothing has that. At least I trust what Signal Protocol is trying to do!

Re: WhatsApp's Signal Protocol integration is now complete

#172

Question for me is still around iCloud backups. Per http://www.popsci.com/whatsapp-now-encrypts-all-messaging-fo... : > However, WhatsApp on iOS still backs up chat logs to iCloud, and despite any effort by Facebook, those could be given to a law enforcement agency. It's not known whether the backups are encrypted, but we've reached out to Open Whisper Systems and will update with any new information. Apple stores iM…

Don't backup your chats?

Re: WhatsApp's Signal Protocol integration is now complete

#173
post #140

How does this compare with Telegram?

By default, Telegram stores a plaintext copy of every message you've ever sent or received on their servers. WhatsApp does end to end encryption using the Signal Protocol by default, and doesn't store anything server side.

Does this mean Whatsapp do peer-to-peer message transfer or messages still pass through whatsapp servers?

Re: WhatsApp's Signal Protocol integration is now complete

#174
Excellent! 3 questions:

- What if the government forces WhatsApp to write and push a targeted software update in order to compromise the end-to-end encryption (I'm of course thinking of the FBI vs Apple case)? Is there a way for the user to be notified?

- Does WhatsApp Auto Backup encrypt messages before sending them to Google Drive or iCloud?

- Would it be possible for WhatsApp Web to rely on backend servers storing an encrypted version of messages, instead of relying on a connection to the user's phone, and still be able to perform keyword search over the encrypted messages with something like github.com/strikeout/mylar?

Re: WhatsApp's Signal Protocol integration is now complete

#175
That's great news - secure-by-default is a huge thing, since it makes encrypted communication more normal. If most of your real-time communication is encrypted, then when and to whom you used encrypted communication isn't leaking valuable information.

The next step is some kind of noise injection into the metadata. There are almost certainly ways to look at who is chatting with who when. It'd be fantastic to automatically generate realistic-looking traffic to hide the normal stuff within. Plus, you'd be adding deniability to any communication you're having.

There's likely some pretty severe battery usage issues with it. If you offload the metadata fuzzing to a proxy server of some sort, then you're adding a vector to filter out that fuzz. It might be too big of a technical tradeoff to be worthwhile.

Re: WhatsApp's Signal Protocol integration is now complete

#176

Does this mean that WhatsApp can talk to Signal Private Messenger app?

No. Signal would probebly like to add Federation as a feature but they have not done so (yet?). So even if Whatsapp would be down to do it, what I don't think, then their would still be a technical issue.

Actor is a messanger that seems to focus on federation and they want to use Singal Protocol as well. So maybe they will devlop software for that. However their is still the issue if Whatsapp would want to do that.

Re: WhatsApp's Signal Protocol integration is now complete

#177
post #142

Earlier quoted context omitted.

What's the incentive of not using TLS?

About 6 round trips, which gives you about a 30s latency on EDGE networks. Doing a key exchange once, retaining it and then doing future communications with just 1 round trip is significantly faster.

Isn't a full TLS handshake 6 messages (thus 3 round trips)? Also with false start and resumption, TLS can also typically achieve 1 roundtrip, right? (I'm also confused by 30s latency for 6 RTT, but maybe I"m too focused on US market, where EDGE latency would be more like 500ms each way.)

Maybe not all of WhatsApp's platforms support the latest TLS improvements though, thus it's easier to roll their own?

Re: WhatsApp's Signal Protocol integration is now complete

#178
post #140

Earlier quoted context omitted.

By default, Telegram stores a plaintext copy of every message you've ever sent or received on their servers. WhatsApp does end to end encryption using the Signal Protocol by default, and doesn't store anything server side.

Cool. So FB/WhatsApp can't even decrypt messages themselves?

If they actually do what they say the do, then yes. Thier is no evidence that they are lying, so for now its probebly save to assume that they can not read your messages.

Re: WhatsApp's Signal Protocol integration is now complete

#179
post #142
post #20

Earlier quoted context omitted.

> They seem to have replaced TLS/SSL between client and server with "Noise Pipes". WhatsApp was already using a custom protocol instead of TLS. We worked with them to transition over to Noise Pipes, which has some advantages over what they were doing before. Also, we've renamed Axolotl to Signal Protocol: https://whispersystems.org/blog/signal-inside-and-out/

What's the incentive of not using TLS?

It's easy to shoot yourself in the foot with TLS (see: OpenSSL). Also, TLS has roots in a time where we knew much less in terms of crypto; as time went on and flaws were discovered, SSL/TLS was patched all around, meaning it has become much harder to implement correctly.

Noise starts from a clean state with modern knowledge of cryptography and modern cryptography. Much easier to understand and replicate, much harder to shoot yourself in the foot with.

TLS brings modularity and evolutivity, much needed in a protocol the scale of HTTP. In Whatsapp's case, Whatsapp controls both the server and the client; it is much easier to transition between versions because all bricks are under control. When you don't need what TLS brings anymore it makes sense to discard it.

As another example: Tarsnap (https://www.tarsnap.com/) uses spiped (https://www.tarsnap.com/spiped.html), a very simple yet powerful mechanism to build an encrypted channel. Its protocol and proof fit in ~100 lines (https://github.com/Tarsnap/spiped/blob/master/README). When you don't need all the jazz provided by TLS (and when you're lucky enough to be able to pre-share keys, which helps a lot) then a simple protocol is good.

Re: WhatsApp's Signal Protocol integration is now complete

#180
post #140

Earlier quoted context omitted.

By default, Telegram stores a plaintext copy of every message you've ever sent or received on their servers. WhatsApp does end to end encryption using the Signal Protocol by default, and doesn't store anything server side.

Don't forget that Telegram uses custom in house encryption and they say "trust us", it's good. Telegram encryption can't be verified.

As long as the clients are open-source and the encryption is end to end, can't it really be verified?

Whatever the server, if the client encryption is reliable, data can't be read on the server side.

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