[mirimir]

Thanks for the clarifications.

> First, on Android 6+ you can just disable the contacts permission and everything works (although you obviously won't see your contact names).

This is very good.

> However, we also spend a lot of time thinking about this class of problems, as well as metadata in general. Right now things are playing out alright for one specific class of attack: [federal subpoena]

Good, so Open Whisper Systems has no metadata. Do any third parties retain metadata about Signal messages?

There's also the issue of mobile numbers. I get that more-or-less anonymous numbers are doable. But arguably, most Signal users don't have anonymous numbers. However, maybe this is a non-issue, if the only data available are "the date and time a user registered with Signal and the last date of a user's connectivity to the Signal service". Is that it?

[exo762]

> Good, so Open Whisper Systems has no metadata. Do any third parties retain metadata about Signal messages?

I'll try to answer to the best of my knowledge (I'm not associated with project, I'm just a happy customer).

Does your ISP know that you are communicating with Signal servers? Yes, IP addresses.

Does it know to whom you are sending messages? No.

Does Google know you are using Signal? Yes.

Does it know whom of your contacts use Signal? Yes, because they have a full list of your contacts and they know if someone has installed Signal.

Does Google know you've sent a message? No.

Does Google know that you are receiving a message? Sometimes, because Signal servers ping your device via GCM with "wake up".

Does Google knows who from your contact list send this message? No, unless you have only one contact who uses Signal.

Can Google infer from pings who is communicating with whom? Yes, although pings are needed only if app has disconnected from server, and this severely limits usefulness of this technique.

Where else may any metadata coming from usage of Signal be? Nowhere.

As for Google having your contact list... Take a look into Flock.

[mirimir]

Thanks :)

I get that Signal is probably the best option for smartphones. And that maybe its vulnerabilities are only relevant for "TAO targets". But the problem is that "TAO targets" is in rapid flux, given developments in automation and AI. So arguably, more and more journalists and dissidents are becoming vulnerable.

And there's the fundamental insecurity of devices with cellular-radio connectivity, and operating systems that users can't control and lock down. Signal can do nothing about that. Even something as simple as reliably obscuring identity in connections to Signal servers is nontrivial.

[exo762]

> But the problem is that "TAO targets" is in rapid flux, given developments in automation and AI.

You are implying that cost of TAO consists mostly of labor costs. Which is false. NSA and friends are not really limited by money. They are limited by amount of unpatched software vulnerabilities. Every use of vulnerability in the wild is a chance of revealing it to world and losing it. Snowden docs reveal the existence of automated software which evaluates chance of vulnerability being revealed by attack. XKeyScore or one of related pieces, AFAIR.

[jhasse]

Does Google know you are using Signal?

Does it know whom of your contacts use Signal?

Does Google know you've sent a message?

Does Google know that you are receiving a message?

Does Google knows who from your contact list send this message?

Can Google infer from pings who is communicating with whom?

Yes to all of those, because they have root on your phone.

[exo762]

You are assuming that Android reports on every step you take. Do you have sources backing this claim?

[jhasse]

It's nearly impossible to find out. But if I trust corporations like Google not to exploit the possibilities, I wouldn't be looking for an open-source alternative to WhatsApp in the first place.

[exo762]

Signal is not positioned as a tool for possible TAO targets. Never was, and never will be. Don't use it and please stop spreading the FUD.

[kuschku]

> Signal is not positioned as a tool for possible TAO targets. Never was, and never will be.

Eh, that’s exactly what it is currently advertised as.

A tool, supported by Snowden, to be used by journalists who are at risk of being under active surveillance by state actors.

That is the very definition of a TAO target.

[jhasse]

What exactly is a TAO target?

[curried_haskell]

Google has root on your phone. Even if they aren't "for now", good security sense says that we should assume that are.

[fnordfnordfnord]

It did formerly via Carrier IQ, which was widely reported in the press. So that's not unprecedented.