Comment by ddtaylor 5 days ago
I don't know signal very well but when I have spoken to others about it they mention that the phone number is the only metadata they will have access to.
This seems like a good example of that being enough metadata to be a big problem.
Unless they compel people at gunpoint (which prevents the government from bringing a case), they will probably not have much luck with this. As soon as a user sets up a passcode or other lock on their phone, it is beyond the ability of even most parts of the US government to look inside.
It's much more likely that the government convinces one member of the group chat to turn on the other members and give up their phone numbers.
> which prevents the government from bringing a case
Genuinely, from outside, it seems like your government doesn't give a damn on what they are and aren't allowed to do.
Yes, but I’m not going to unlock my phone with a passcode, and unlike biometric unlock they have no way to force me to unlock my phone.
The district courts will eventually back me up on this. Our country has fallen a long way, but the district courts have remained good, and my case is unlikely to be one that goes up to appellate courts, where things get much worse.
There’s an important distinction: the government doesn’t care about what it is allowed to do, but it is still limited by what it is not capable of doing. It’s important to understand that they still do have many constraints they operate under, and that we need to find and exploit those constraints as much as possible while we fight them
You have to remember that "the government" is not a monolith. Evidence goes before a judge who is (supposed to be) independent, and cases are tried in front of a jury of citizens. In the future that system may fall but for now it's working properly. Except for the Supreme Court... which is a giant wrench in the idea the system still works, but that doesn't mean a lower court judge won't jettison evidence obtained by gunpoint.
They haven't for a long time, just that most of the time they were doing things we thought was for good (EPA, civil rights act, controlled substance act, etc) and we thereby entered a post-constitutional world to let that stuff slide by despite the 10th amendment limiting the federal powers to enumerated powers.
Eventually we got used to letting the feds slide on all the good things to the point everything was just operating on slick ice, and people like Trump just pushed it to the next logical step which is to also use the post-constitutional world to his own personal advantage and for gross tyranny against the populace.
They'll just threaten to throw the book at you if you don't unlock your phone, and if you aren't rich, your lawyer will tell you to take the plea deal they offer because it beats sitting in prison until you die.
If you aren't saving people's phone numbers in your own contacts, signal isn't storing them in group chats (and even if you are, it doesn't say which number, just that you have a contact with them).
Signal doesn't share numbers by default and hasn't for a few years now. And you can toggle a setting to remove your number from contact discovery/lookup entirely if you are so inclined.
Which is just a redux of what I find myself saying constantly: privacy usually isn't even the problem. The problem is the people kicking in your door.
If you're willing to kick in doors to suppress legal rights, then having accurate information isn't necessary at all.
If your resistance plan is to chat about stuff privately, then by definition you're also not doing much resisting to you know, the door kicking.
> it is beyond the ability of even most parts of the US government to look inside.
I'm sure the Israeli spyware companies can help with that.
Although then they'd have to start burning their zero days to just go after protestors, which I doubt they're willing to do. I imagine they like to save those for bigger targets.
Cellebrite still requires the device to be confiscated. So if they are trying for mass surveillance, they'll have to rely on phishing or zero day exploits to get their spyware on the device to intercept messages. These tend to get patched shortly after being seen in the wild (like the recent WhatsApp one), so they need to decide if its worth it to burn that zero day or not.
There are multiple companies that can get different amounts of information off of locked phones including iPhones, and they work with LE.
I’m also curious what they could get off of cloud backups. Thinking in terms of auth, keys, etc. For SMS it’s almost as good as phone access, but I am not sure for apps.
it is difficult to wrench someone when you do not know who they are
I wonder whether the protesters could opt for offshore alternatives that don't require exposing their phone number to a company that could be compelled to reveal it by US law. For example, there is Threema[1], a Swiss option priced at 5 euros one-time. It is interesting on Android as you can pay anonymously[2], therefore it doesn't depend on Google Play and its services (they offer Threema Push services of their own.) If your threat model includes traffic analysis, likely none of it would make much difference as far as US state-side sigint product line is concerned, but with Threema a determined party might as well get a chance! Arguably, the US protest organisers must be prepared for the situation to escalate, and adjust their security model accordingly: GrapheneOS, Mullvad subscription with DAITA countermeasures, Threema for Android, pay for everything with Monero?
It's worth noting that the way Signal's architecture is set up, Signal the organisation doesn't have access to users' phone numbers.
They technically have logs from when verification happens (as that goes through an SMS verification service) but that just documents that you have an account/when you registered. And it's unclear whether those records are available anymore since no warrants have been issued since they moved to the new username system.
And the actual profile and contact discovery infra is all designed to be actively hostile to snooping on identifiable information even with hardware access (requiring compromise of secure enclaves + multiple levels of obfuscation and cryptographic anti-extraction techniques on top).
Perhaps you're right that they couldn't be compelled by law to reveal it, then! However, I can still find people on Signal using their phone number, by design. If they can do that, surely there is sufficient information, and appropriate means, for US state-side signals intelligence to do so, too. I don't think Signal self-hosts their infrastructure, so it wouldn't be much of a challenge considering it's a priority target.
Now, whether FBI and friends would be determined to use PII obtained in this way to that end—is a point of contention, but why take the chance?
Better yet, don't expose your PII to third parties in the first place.
Note that Threema has had a recent change in ownership to a German investment firm. Supposedly nothing will change but I can’t help but be wary
The alarming extent of US-affiliated signals intelligence collection is well-documented, but in the case of Threema it's largely inconsequential; you can still purchase the license for it anonymously, optionally build from source, and actively resist traffic analysis when using it.
That is to say: it allows a determined party to largely remain anonymous even in the face of upstream provider's compromise.
It appears to be primarily getting agents into the chats. To me the questionable conduct is their NPSM-7-adjacent redefining of legal political categories and activities as "terrorists/-ism" for the purpose of legal harassment or worse. Whether that is technically legal or not it should be outrageous to the public.
I don't think it's much of a problem at all. Many of the protesters and observers are not hiding their identities, so finding their phone number isn't a problem. Even with content, coordinating legal activities isn't a problem either.
I would never agree with you. protestors behaving legally or practicing civil disobedience can still have their lives ruined by people in power.
https://www.phoenixnewtimes.com/news/arizona-supreme-court-s...
The literal point of civil disobedience is accepting that you may end up in jail:
"Any man who breaks a law that conscience tells him is unjust and willingly accepts the penalty by staying in jail to arouse the conscience of the community on the injustice of the law is at that moment expressing the very highest respect for the law."
-- Letter from the Birmingham Jail, MLK Jr: https://people.uncw.edu/schmidt/201Stuff/F14/B%20SophistSocr...
This works when protesting an unjust law with known penalties. King knew he would be arrested and had an approximate idea on the range of time he could be incarcerated for. I don't know if it's the same bargain when you are subjecting yourself to an actor that does not believe it is bound by the law.
If you let the government stomp on your constitutional rights and willingly go to jail on unconstitutional grounds, then that's not respect for the law. That's respect for injustice.
Accepting jail over 1A protected protests only proves you're weak (not in the morally deficient way, just from a physical possibilities way) enough to be taken. No one thinks more highly of you or your 'respect for the law' for being caught and imprisoned in such case, though we might not think lesser of you, since we all understand it is often a suicide mission to resist it.
Importantly this definition references an individual’s conscience. Seditious conspiracy is another matter. Here is the statute:
> If two or more persons in any State or Territory, or in any place subject to the jurisdiction of the United States, conspire to overthrow, put down, or to destroy by force the Government of the United States, or to levy war against them, or to oppose by force the authority thereof, or by force to prevent, hinder, or delay the execution of any law of the United States, or by force to seize, take, or possess any property of the United States contrary to the authority thereof, they shall each be fined under this title or imprisoned not more than twenty years, or both.
A group chat coordinating use of force may be tough.
> protestors behaving legally or practicing civil disobedience can still have their lives ruined by people in power.
They surely can. But the point was more than the people in power don't really need Signal metadata to do that. On the lists of security concerns modern protestors need to be worrying about, Signal really just isn't very high.
Some of the signal messages I've seen screenshotted (granted screenshots can be altered) make it seem like the participants have access to some sort of ALPR data to track vehicles that they think are ICE. That would probably be an illegal use of that data if true.
The government falling victim to ALPR for once might actually be the push we need to get some reform. That said, they'll probably try to ban it for everybody but themselves. Never before have they had such comprehensive surveillance and I don't expect them to give it up easily.
I remember having to explain to you that the CFAA doesn't apply to German citizens in Germany committing acts against a German website, so I'll take that legal advice with a few Dead Seas worth of salt.
Tow trucks have ALPR cameras to find repossessions. Plenty of private options for obtaining that sort of data; you can buy your own for a couple hundred bucks. https://linovision.com/products/2-mp-deepinview-anpr-box-wit...
That seems like a weak argument.
I mean, carrying a weapon is a 2nd amendment right, but if I bring it to a protest and then start intimidating people with it, the police going after me is not "Government intimidation of the practice of constitutional rights".
Protesting is a constitution right, but if you break the law while protesting, you're fair game for prosecution.
conspiracy charges are a thing, and they'll only need a few examples of manifestly illegal interference.
it will be quite easy for a prosecutor to charge lots of these people.
it's been done for less, and even if the case is thrown out it can drag on for years and involve jail time before any conviction.
If they could arrest people for what they've been doing, they would have already arrested people. And they have arrested a few here and there for "assault" (things like daring to react when being shoved by an annoyed officer), but the thing that's really pissing DHS off is that the protesters and observers are not breaking the law.
Remember that most of the participants in J6 walked away and were later rounded up and arrested across the country once the FBI had collected voluminous digital and surveillance evidence to support prosecution.
That may be true in the abstract (although it doesn't matter if the cops think you're breaking the law. What matters is whether or not a judge does).
However, neither Border patrol nor ICE have been exhibiting thoughtfulness or patience, so I doubt they're playing any such long game.
I highly recommend this book. It goes into who funds these things.
https://www.amazon.com/Surveillance-Valley-Military-History-...
Was starting to think about setting up a neighborhood Signal group, but now thinking that maybe something like Briar might be safer... only problem is that Briar only works on Android which is going to exclude a lot of iPhone users.
Why wouldn't you just use random abandoned forums or web article message threads? Iirc this is what teenagers used to do when schools banned various social media but not devices. Just put the URL in a discrete qr code that only a person in the neighborhood could see.
I spent a dozen years in SF, where my friend circles routinely used Signal. It's my primary messaging app, including to family and childhood friends.
I live in NY now. Just today, I got a message from a close friend who also did SF->NY "I'm deleting Signal to get more space on my phone, because nobody here uses it. Find me on WhatsApp or SMS."
To a naïve audience, Signal can have a stigma "I don't do anything illegal, so why should I bother maintaining yet-another messenger whose core competency is private messaging?" Signal is reasonably mainstream, and there are still a lot of people who won't use it.
I suspect you'll have an uphill battle using something even more obscure.
> Signal can have a stigma "I don't do anything illegal, so why should I bother ..."
Aside: I see similar attitudes when I mention I use VPN all of the time
but this is not a technical attack that returns the metadata.
much more closer to the $5 wrench attack
I've been hearing for years people say "Signal requires phone number therefore I don't use it", and I've been hearing them mocked for years.
Turns out they were right.
They weren't though? Signal requires a phone number to sign up and it is linked to your account but your phone number is not used in the under the hood account or device identification, it is not shared by default, your number can be entirely removed from contact disovery if you wish, and even if they got a warrant or were tapping signal infra directly, it'd be extremely non trivial to extract user phone numbers.
https://signal.org/blog/phone-number-privacy-usernames/
https://signal.org/blog/sealed-sender/
https://signal.org/blog/private-contact-discovery/
In past instances where Signal has complied with warrants, such as the 2021 and 2024 Santa Clara County cases, the records they provided included phone numbers to identify the specific accounts for which data was available. This was necessary to specify which requested accounts (identified by phone numbers in the warrants) had associated metadata, such as account creation timestamps and last connection dates.
Yep however that only exposes a value of "last time the user registered/verified their account via phone number activation" and "last day the app connected to the signal servers".
There isn't really anything you can do with that information. The first value is already accessible via other methods (since the phone companies carry those records and will comply with warrants). And for pretty much anyone with signal installed that second value is going to essentially always be the day the search occurred.
And like another user mentioned, the most recent of those warrants is from the day before they moved to username based identification so it is unclear whether the same amount of data is still extractable.
Which of those links actually say that your phone number is private from Signal? If anything, this passage makes it sound like it's the reverse, because they specifically call out usernames not being stored in plaintext, but not phone numbers.
>We have also worked to ensure that keeping your phone number private from the people you speak with doesn’t necessitate giving more personal information to Signal. Your username is not stored in plaintext, meaning that Signal cannot easily see or produce the usernames of given accounts.
> it'd be extremely non trivial
Extremely non trivial. What I'm hearing is "security by obfuscation".
Absolutely nothing in this article is related to feds using conversation metadata to map participants, so, no they weren’t.
If you follow the X chatter on this, some folks got into the groups and tracked all the numbers, their contributions, and when they went "on shift" or "off".
I don't really think Signal tech has anything to do with this.
Yeah. It's notable they didn't crack the crypto. In the 90s when I was a young cypherpunk, I had this idea that when strong crypto was ubiquitous, certainly people would be smart enough to understand its role was only to force bad guys to attack the "higher levels" like attacking human expectations of privacy on a public channel. It was probably unrealistic to assume everyone would automatically understand subtle details of technology.
As a reminder... if you don't know all the people in your encrypted group chat, you could be talking to the man.
Signal's use of phone numbers is the least of your issues if you've reached this level of inspection. Signal could be the most pristine perfect thing in the world, and the traffic from the rest of your phone is exactly as exposing as your phone number is when your enemy is the US government who can force cooperation from the infrastructure providers.
Your point is correct but irrelevant to this conversation.
The question here is NOT "if Signal didn't leak your phone number could you still get screwed?" Of course you could, no one is disputing that.
The question is "if you did everything else perfect, but use Signal could the phone number be used to screw you?" The answer is ALSO of course, but the reason why we're talking about it is that this point was made to the creator of Signal many many times over the years, and he dismissed it and his fanboys ridiculed it.
I talked to Moxie about this 20 years ago at DefCon and he shrugged his shoulders and said "well... it's better than the alternative." He has a point. Signal is probably better than Facebook Messenger or SMS. Maybe there's a market for something better.
Is there any reason they didn't use email? It seems like something that would have been easier to keep some anonymity., while still allowing the person to authenticate.
I wasn't assuming the actual messages would go through email. I assumed they just needed that for a onetime setup. Isn't that the only reason for using a phone number currently?
I remember listening to his talks and had some respect for him. He could defeat any argument about any perceived security regarding any facet of tech. Not so much any more. He knows as well as I do anything on a phone can never be secure. I get why he did it. That little boat needed an upgrade and I would do it too. Of course this topic evokes some serious psychological responses in most people. Wait for it.
I have no idea if that was true 20 years ago, but it's not true now. XMPP doesn't have this problem; your host instance knows your IP but you can connect via Tor.
I could have sworn Signal adopted usernames sometime back, but in my eyes its a little too late.
I think the deal is you marry the strong crypto with a human mediated security process which provides high confidence the message sender maps to the human you think they are. And even if they are, they could be a narc. Nothing in strong crypto prevents narcs in whom ill-advised trust has been granted from copying messages they're getting over the encrypted channel and forwarding them to the man.
And even then, a trusted participant could not understand they're not supposed to give their private keys out or could be rubber-hosed into revealing their key pin. All sorts of ways to subvert "secure" messaging besides breaking the crypto.
I guess what I'm saying is "Strong cryptography is required, but not sufficient to ensure secure messaging."
Yes. Cheap–identity systems such as Session and SimpleX are trivially vulnerable to this, and your only defence is to not give out your address as they are unguessable. If you have someone's address, you can spam them, and they can't stop it except by deleting the app or resetting to a new address and losing all their contacts.
SimpleX does better than Session because the address used to add new contacts is different from the address used with any existing contact and is independently revocable. But if that address is out there, you can receive a full queue of spam contacts before you next open the SimpleX app.
Both Session and SimpleX are trivially vulnerable to storage DoS as well.
There are a lot of solutions to denial of service attacks than to collect personal information. Plus, you know, you can always delete an account later? If what Signal says is true, then this amounts to a few records in their database which isn't cause for concern IMO
The steps to trouble:
- identify who owns the number
- compel that person to give unlocked phone
- government can read messages of _all_ people in group chat not just that person
Corollary:
Disappearing messages severely limits what can be read