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Facebook Messenger begins testing end-to-end encryption using Signal Protocol

whispersystems.org

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Re: Facebook Messenger begins testing end-to-end encryption using Signal Protocol

#121
post #3

From what is written, I understand this to mean that users can select this feature for specific conversations. That not all messages are subject to this encryption. I am not usually one for paranoia, but is anyone else becoming more suspicious about Facebooks motivations and involvement with gov? This feature is a massive boost for intelligence services dealing with unsophisticated actors. This reduces the haystack s…

> Why doesn't FB just apply encryption on all messages? The same reason Gmail can't work with end-to-end encryption--they want to advertise at you based on message content. I highly doubt there is any government intervention in FB's business strategy, but there seems to be plenty of cooperation after the business decisions are made. (The same is largely true with Microsoft, Google, and yes, even Apple.) It's not real…

> The same reason Gmail can't work with end-to-end encryption--they want to advertise at you based on message content.

Facebook can do fine without that information: they have more information than they can develop ad services for at the moment; they could use a lot more engineers though. The goodwill from the dev community in allowing appropriate targeting is far more important to them.

Two good examples being location and language: you can advertise for people in a certain place or who speak a certain language, but there are many unserved combinations, like tourists, language minorities and commuters. In my case, I’d love to see ads on learning Swedish: Facebook can see some of my friends speak it, and this is new.

Source: worked for Fb, but in Engagement, not the Ads team; offered a lot of targeting suggestions, but most where “presumably not the biggest opportunities (they) could work on”. At Facebook’s scale, we are talking really big numbers.

Re: Facebook Messenger begins testing end-to-end encryption using Signal Protocol

#122
post #28
post #17

Earlier quoted context omitted.

> The same reason Gmail can't work with end-to-end encryption--they want to advertise at you based on message content. I wonder how they'd do if they were more open about it. "You're getting Gmail for free because we read your email and advertise to you. However, if you want to pay for a premium account (or Google Apps for Work) then we won't advertise to you, won't read your email and we'll even make end-to-end encr…

The wording "we read your email" isn't quite accurate. There is nobody at google who goes through davb's emails one by one.

But they can. I doubt they do, because it's just not practical, but they do have the ability to

Re: Facebook Messenger begins testing end-to-end encryption using Signal Protocol

#123

Earlier quoted context omitted.

Am I confused? Isn't it impossible to brute force a single properly encrypted message? (where properly means that the protocol and implementation are sound and so on)

This makes a lot of assumptions, like the NSA hasn't broken algorithms we consider secure, that they're not somehow sharing keys, or using a gimped algorithm on purpose, etc.

Sure, but those assumptions are implicit in the statement I replied to Multi-millions of FB messages must be sent every day, brute-forcing encryption on all of these is probably not possible. A small % marked as 'secret conversation'? Much easier.

If you don't trust Facebook, you don't need to evaluate the quality of their implementation of secret messaging, you just shouldn't use it.

Re: Facebook Messenger begins testing end-to-end encryption using Signal Protocol

#124
post #3

From what is written, I understand this to mean that users can select this feature for specific conversations. That not all messages are subject to this encryption. I am not usually one for paranoia, but is anyone else becoming more suspicious about Facebooks motivations and involvement with gov? This feature is a massive boost for intelligence services dealing with unsophisticated actors. This reduces the haystack s…

"brute-forcing encryption on all of these is probably not possible. A small % marked as 'secret conversation'? Much easier."

They probably wouldn't have to brute-force them. Backdooring's still quite possible - the NSA are perfectly capable of compelling Facebook to install a keylogger in their app.

Re: Facebook Messenger begins testing end-to-end encryption using Signal Protocol

#125
post #53

Earlier quoted context omitted.

Could you elaborate on why applying signal protocal in a browser is next to impossible?

Well, the keywords there are next to. Like @remy_ implied, you need a mechanism for guaranteeing that the logic you're executing in-browser is protected from server compromise. That's where the Cyph example came in, since as far as I can tell, Cyph is the team to have hacked together a solution to that dilemma, though Cyph also is not using the Signal Protocol right now. Anyway, there's an upcoming defcon talk which'…

Cyph's solution for this, last I saw it, is a Rube Goldberg machine of rolling HPKP pins used in attempt to keep the application from reloading itself from its own servers. It's incredibly complicated. And no matter how much asm.js you use, it's still crypto running in a browser instance. There are other very significant problems with browser crypto --- problems that even affect Chrome Applications.

Re: Facebook Messenger begins testing end-to-end encryption using Signal Protocol

#126
post #3

From what is written, I understand this to mean that users can select this feature for specific conversations. That not all messages are subject to this encryption. I am not usually one for paranoia, but is anyone else becoming more suspicious about Facebooks motivations and involvement with gov? This feature is a massive boost for intelligence services dealing with unsophisticated actors. This reduces the haystack s…

Reasons from @alexstamos (CSO @ Facebook): - FBM is multi-device, and we'd like to see E2E usability improve to support this. For now, pick one device and keys never leave it - Secret conversations don't currently support popular features like searching message history, switching devices, voice/video, etc - Hundreds of millions use Messenger from a web browser. No secure way to verify code or store keys without routi…

> No secure way to verify code or store keys without routing through mobile.

Weeeeeeell, not quite. Every device and browser the user uses can get it's own private key, and then you use Facebook's central servers and SSL to exchange keys.

If I don't trust Facebook for key exchange, then I can't trust them with their app. Any encryption they implement, they can trivially circumvent by putting a backdoor in their app.

But if I trust their (closed source, frequently updated) app at all, then I can trust them to relay people my public keys. Especially since MITM can be discovered by comparing hashes over a hard to manipulate channel (telefone, video, or IRL).

And if you're really paranoid, you could think about using an open-source app and letting a trusted third party handle the keys.

Re: Facebook Messenger begins testing end-to-end encryption using Signal Protocol

#127

So ... no comment on the choice of picture in the blog post? I hadn't heard of Jules Bonnot, but found the wikipedia article illuminating: https://en.wikipedia.org/wiki/Jules_Bonnot This seems like it's a subtle endorsement for using Open Whisper Systems for criminal activities. Is it just me, or does that seem like the wrong image to gravitate towards?

OWS quite often use anarchist figures and quotes in their example images for blog posts, this is nothing new.

Re: Facebook Messenger begins testing end-to-end encryption using Signal Protocol

#128
post #53

Earlier quoted context omitted.

Well, the keywords there are next to. Like @remy_ implied, you need a mechanism for guaranteeing that the logic you're executing in-browser is protected from server compromise. That's where the Cyph example came in, since as far as I can tell, Cyph is the team to have hacked together a solution to that dilemma, though Cyph also is not using the Signal Protocol right now. Anyway, there's an upcoming defcon talk which'…

Cyph's solution for this, last I saw it, is a Rube Goldberg machine of rolling HPKP pins used in attempt to keep the application from reloading itself from its own servers. It's incredibly complicated. And no matter how much asm.js you use, it's still crypto running in a browser instance. There are other very significant problems with browser crypto --- problems that even affect Chrome Applications.

You and I+Cure53+others will probably always disagree on this topic since you've always been the primary catalyst for dissent on this, but it's not at all complicated nor deserving of the analogy to a Rube Goldberg machine.

It's been well vetted enough. It might be a hack, but it's a sufficiently effective hack. We can agree to disagree :)

You coming to either Black Hat or DEF CON? Let me at least connect the two of you after the AppSec Glory talk.

Re: Facebook Messenger begins testing end-to-end encryption using Signal Protocol

#130
post #3

From what is written, I understand this to mean that users can select this feature for specific conversations. That not all messages are subject to this encryption. I am not usually one for paranoia, but is anyone else becoming more suspicious about Facebooks motivations and involvement with gov? This feature is a massive boost for intelligence services dealing with unsophisticated actors. This reduces the haystack s…

Reasons from @alexstamos (CSO @ Facebook): - FBM is multi-device, and we'd like to see E2E usability improve to support this. For now, pick one device and keys never leave it - Secret conversations don't currently support popular features like searching message history, switching devices, voice/video, etc - Hundreds of millions use Messenger from a web browser. No secure way to verify code or store keys without routi…

> "We don't want to disrupt people's current experience."

Hahaha.

Sounded plausible until I saw that line. When did FB suddenly start caring about that?

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