On its 10th anniversary, Signal’s president wants to remind you that the world’s most secure communications platform is a nonprofit. It’s free. It doesn’t track you or serve you ads. It pays its engineers very well. And it’s a go-to app for hundreds of millions of people.
Yeah, Signal is more than encrypted messaging it’s a metadata harvesting platform. It collects phone numbers of its users, which can be used to identify people making it a data collection tool that resides on a central server in the US. By cross-referencing these identities with data from other companies like Google or Meta, the government can create a comprehensive picture of people’s connections and affiliations.
This allows identifying people of interest and building detailed graphs of their relationships. Signal may seem like an innocuous messaging app on the surface, but it cold easily play a crucial role in government data collection efforts.
Strictly speaking, the social graph harvesting portion would be under the Google umbrella, as, IIRC, Signal relies on Google Play Services for delivering messages to recipients. Signal’s sealed sender and “allow sealed sender from anyone” options go part way to addressing this problem, but last I checked, neither of those options are enabled by default.
However, sealed sender on its own isn’t helpful for preventing build-up of social graphs. Under normal circumstances, Google Play Services knows the IP address of the sending and receiving device, regardless of whether or not sealed sender is enabled. And we already know, thanks to Snowden, that the feds have been vacuuming up all of Google’s data for over a decade now. Under normal circumstances, Google/the feds/the NSA can make very educated guesses about who is talking to who.
In order to avoid a build-up of social graphs, you need both the sealed sender feature and an anonymity overlay network, to make the IP addresses gathered not be tied back to the endpoints. You can do this. There is the Orbot app for Android which you can install, and have it route Signal app traffic through the Tor network, meaning that Google Play Services will see a sealed sender envelope emanating from the Tor Network, and have no (easy) way of linking that envelope back to a particular sender device.
Under this regime, the most Google/the feds/the NSA can accumulate is that different users receive messages from unknown people at particular times (and if you’re willing to sacrifice low latency with something like the I2P network, then even the particular times go away). If Signal were to go all in on having client-side spam protection, then that too would add a layer of plausible deniability to recipients; any particular message received could well be spam. Hell, spam practically becomes a feature of the network at that point, muddying the social graph waters further.
That Signal has
Not made sealed sender and “allow sealed sender from anyone” the default, and
Not incorporated anonymizing overlay routing via tor (or some other network like I2P) into the app itself, and
Is still in operation in the heart of the U.S. empire
tells me that the Feds/the NSA are content with the current status quo. They get to know the vast, vast majority of who is talking (privately) to who, in practically real time, along with copious details on the endpoint devices, should they deem tailored access operations/TAO a necessary addition to their surveillance to fully compromise the endpoints and get message info as well as metadata. And the handful of people that jump through the hoops of
Enabling sealed sender
Enabling “allow sealed sender from anyone”
Routing app traffic over an anonymizing overlay network (and ideally having their recipients also do so)
can instead be marked for more intensive human intelligence operations as needed.
Finally, the requirement of a phone number makes the Fed’s/the NSA’s job much easier for getting an initial “fix” on recipients that they catch via attempts to surveil the anonymizing overlay network (as we know the NSA tries to). If they get even one envelope, they know which phone company to go knocking on to get info on where that number is, who it belongs to, etc.
This too can be subverted by getting burner SIMs, but that is a difficult task. A task that could be obviated if Signal instead allowed anonymous sign-ups to its network.
That Signal has pushed back hard on every attempt to remove the need for a phone number tells me that they have already been told by the Feds/the NSA that that is a red line, and that, should they drop that requirement, Signal’s days of being a cushy non-profit for petite bourgeois San Francisco cypherpunks would quickly come to an end.
Strictly speaking, you can download it directly from their website, but IIRC, the build will still default to trying to use Google Play Services, and only fall back to a different service if Google Play Services is not on the device. Signal really, really wants to give Google insight into who is messaging who.
Anyone who has any experience with centralized databases, would be able to tell you how useless sealed sender is. With message recipients and timestamps, it’d be trivial to discover who the senders are.
Also, signal has always had a cozy relationship with the US (radio free asia was it’s initial funder) . After yasha levine posted an article critical of signal a few years back, RFA even tried to do damage control at a privacy conference on signal s behalf:
Libby Liu, president of Radio Free Asia stated:
Our primary interest is to make sure the extended OTF network and the Internet Freedom community are not spooked by the [Yasha Levine’s] article (no pun intended). Fortunately all the major players in the community are together in Valencia this week - and report out from there indicates they remain comfortable with OTF/RFA.
These are high-up US government employees trying to further spread signal.
Law enforcement doesn’t request data frequently enough in order to build a social graph. Also they probably don’t need to as Google and Apple likely have your contacts.
Saying that it is somehow a tool for mass surveillance is frankly wrong. It has its issues but it also balances ease of use. It is the most successful secure messager out there. (WhatsApp doesn’t count)
Sure it has problems. I personally don’t understand there refusal to be on F-droid. However, phone numbers are great for ease of use and help prevent spam. You need to give your personal information to get a phone number. Signal also has very nice video calls which no other messager can seem to replicate.
Law enforcement doesn’t request data frequently enough in order to build a social graph. Also they probably don’t need to as Google and Apple likely have your contacts.
They don’t need to request data. They have first-class access to the data themselves. Snowden informed us of this over a decade ago.
Saying that it is somehow a tool for mass surveillance is frankly wrong.
Signal per se is not the mass surveillance tool. Its dependence on Google is the mass surveillance tool.
However, phone numbers are great for ease of use and help prevent spam.
And there’s nothing wrong with allowing that ease-of-use flow for users that don’t need anonymity. The problem is disallowing anonymous users.
I’m not speaking of hard dependence as in “the app can’t work without it.” I’m speaking to the default behavior of the Signal application:
It connects to Google
It does not make efforts to anonymize traffic
It does makes efforts to prevent anonymous sign-ups
Molly FOSS choosing different defaults doesn’t change the fact that the “Signal” client app, which accounts for the vast majority of clients within the network, is dependent on Google.
And in either case – using Google’s Firebase system, or using Signal’s websocket system – the metadata under discussion is still not protected; the NSA doesn’t care if they’re wired into Google’s data centers or Signal’s. They’ll be snooping the connections either way. And in either case, the requirement of a phone number is still present.
Perhaps I should restate my claim:
Signal per se is not the mass surveillance tool. Its dependence on Google design choices of (1) not forcing an anonymization overlay, and (2) forcing the use of a phone number, is the mass surveillance tool.
Strictly speaking, the social graph harvesting portion would be under the Google umbrella, as, IIRC, Signal relies on Google Play Services for delivering messages to recipients. Signal’s sealed sender and “allow sealed sender from anyone” options go part way to addressing this problem, but last I checked, neither of those options are enabled by default.
However, sealed sender on its own isn’t helpful for preventing build-up of social graphs. Under normal circumstances, Google Play Services knows the IP address of the sending and receiving device, regardless of whether or not sealed sender is enabled. And we already know, thanks to Snowden, that the feds have been vacuuming up all of Google’s data for over a decade now. Under normal circumstances, Google/the feds/the NSA can make very educated guesses about who is talking to who.
In order to avoid a build-up of social graphs, you need both the sealed sender feature and an anonymity overlay network, to make the IP addresses gathered not be tied back to the endpoints. You can do this. There is the Orbot app for Android which you can install, and have it route Signal app traffic through the Tor network, meaning that Google Play Services will see a sealed sender envelope emanating from the Tor Network, and have no (easy) way of linking that envelope back to a particular sender device.
Under this regime, the most Google/the feds/the NSA can accumulate is that different users receive messages from unknown people at particular times (and if you’re willing to sacrifice low latency with something like the I2P network, then even the particular times go away). If Signal were to go all in on having client-side spam protection, then that too would add a layer of plausible deniability to recipients; any particular message received could well be spam. Hell, spam practically becomes a feature of the network at that point, muddying the social graph waters further.
That Signal has
tells me that the Feds/the NSA are content with the current status quo. They get to know the vast, vast majority of who is talking (privately) to who, in practically real time, along with copious details on the endpoint devices, should they deem tailored access operations/TAO a necessary addition to their surveillance to fully compromise the endpoints and get message info as well as metadata. And the handful of people that jump through the hoops of
can instead be marked for more intensive human intelligence operations as needed.
Finally, the requirement of a phone number makes the Fed’s/the NSA’s job much easier for getting an initial “fix” on recipients that they catch via attempts to surveil the anonymizing overlay network (as we know the NSA tries to). If they get even one envelope, they know which phone company to go knocking on to get info on where that number is, who it belongs to, etc.
This too can be subverted by getting burner SIMs, but that is a difficult task. A task that could be obviated if Signal instead allowed anonymous sign-ups to its network.
That Signal has pushed back hard on every attempt to remove the need for a phone number tells me that they have already been told by the Feds/the NSA that that is a red line, and that, should they drop that requirement, Signal’s days of being a cushy non-profit for petite bourgeois San Francisco cypherpunks would quickly come to an end.
Incidentally, this explains why Signal insists that the app has to be installed through the Play store as opposed to f-droid.
Strictly speaking, you can download it directly from their website, but IIRC, the build will still default to trying to use Google Play Services, and only fall back to a different service if Google Play Services is not on the device. Signal really, really wants to give Google insight into who is messaging who.
exactly, vast majority of users will be going through Google’s store when installing it
Anyone who has any experience with centralized databases, would be able to tell you how useless sealed sender is. With message recipients and timestamps, it’d be trivial to discover who the senders are.
Also, signal has always had a cozy relationship with the US (radio free asia was it’s initial funder) . After yasha levine posted an article critical of signal a few years back, RFA even tried to do damage control at a privacy conference on signal s behalf:
Libby Liu, president of Radio Free Asia stated:
These are high-up US government employees trying to further spread signal.
You can read more about this here.
Law enforcement doesn’t request data frequently enough in order to build a social graph. Also they probably don’t need to as Google and Apple likely have your contacts.
Saying that it is somehow a tool for mass surveillance is frankly wrong. It has its issues but it also balances ease of use. It is the most successful secure messager out there. (WhatsApp doesn’t count)
Sure it has problems. I personally don’t understand there refusal to be on F-droid. However, phone numbers are great for ease of use and help prevent spam. You need to give your personal information to get a phone number. Signal also has very nice video calls which no other messager can seem to replicate.
They don’t need to request data. They have first-class access to the data themselves. Snowden informed us of this over a decade ago.
Signal per se is not the mass surveillance tool. Its dependence on Google is the mass surveillance tool.
And there’s nothing wrong with allowing that ease-of-use flow for users that don’t need anonymity. The problem is disallowing anonymous users.
Signal is not dependent on Google. Also to my knowledge Signal isn’t part of AT&T
It literally is though.
If that were the case Molly FOSS wouldn’t exist
I’m not speaking of hard dependence as in “the app can’t work without it.” I’m speaking to the default behavior of the Signal application:
Molly FOSS choosing different defaults doesn’t change the fact that the “Signal” client app, which accounts for the vast majority of clients within the network, is dependent on Google.
And in either case – using Google’s Firebase system, or using Signal’s websocket system – the metadata under discussion is still not protected; the NSA doesn’t care if they’re wired into Google’s data centers or Signal’s. They’ll be snooping the connections either way. And in either case, the requirement of a phone number is still present.
Perhaps I should restate my claim:
A really excellent writeup!