Comment by tamimio
1 year ago
> Obviously if your phone is compromised your e2ee chat is not safe.
Pretty much, a lot of people think that seeing E2EE means everything is safe, which I believe gives a false sense of security. You can have your phone compromised (especially when I know your phone number, Signal I’m looking at you) or be subject to other means of attacks, exposing everything. I would rather know that this app is not secure so I don’t share anything important, while keeping secure communication to other means.
Not only that. If they want to intercept e2e chats it's possible with a MITM attack, that if you control the server it's not a difficult thing to do. Of course the users if they check the keys they see they are different, but practically no one does that.
And I think WhatsApp probably does it, otherwise why the authorities never complied that WhatsApp did not let them see the conversations?
WhatsApp has defaulted to aggressively storing allegedly "E2EE" conversations without any form of encryption in Google Drive (freely) for years. And it would seem they are also currently in possession of the keys to decrypt them when you restore such backups from another device without the key stored on it (that lately cannot be extracted without exploits or root access anyway). Facebook/Meta has often expressed their love for the practice of client-side scanning or parallelly sending data to their servers, but it doesn't seem the case for WhatsApp yet, so what measures they take to remain compliant with the ever-increasing surveillance practices remains to speculation. For a somewhat educated user that knows to opt-out of online backups every time it's prompted by the application, I'd say it's probably safer than normal Telegram chats, but very far from flawless.
> And I think WhatsApp probably does it
Rule of thumb: never trust anything Facebook. I’m sure sending your messages through mail is more secure and private than WhatsApp these days.
Stealing someone's phone number wouldn't give you any Signal data, as all the messages have perfect forward secrecy, though, right? And all contacts would see an alert that your security number had changed. Not completely foolproof, and I would like Signal to use something other than phone numbers for accounts, but it's pretty good.
Knowing someone's phone number is enough to potentially compromise it. Sophisticated methods can involve zero-click attacks, where just sending you an SMS that you won’t even see can lead to a compromised device. You can check how Tucker got his Signal conversation exposed.
Matrix is far better in terms of security than Signal, but Matrix is far behind compared to Telegram features.
You seem to be living on this weird balance of having no threat model. This is what your post implies
1. Signal is bad and insecure because registering user account requires giving a phone number. 2. Matrix is better, it fixes this by registering with emails (although emails also have zero click vulnerabilities) 3. Telegram is better than Matrix, it's more usable (even though it also requires a phone number like Signal)
So pick a lane, is requiring a phone-number a litmus-test for you or not. Is zero-click vulnerability something that needs to be addressed? How do you deal with malicious contacts or people in public groups sending zero-click links?
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That's a good point. I looked into using Matrix before I switched to Signal, but the user experience just in creating an account was pretty abysmal, at least at the time. As I was recommending it to non-tech people, I ended up going with Signal.
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One does not need to keep the SIM card with the phone number required for registration in the phone.
Also telegram has an additional password option if you want to login which avoids phone number hijack. Also if you hijack an account the secret chats don’t appear. They are bounded to the device.
There's also an option in the settings that translates into taking over a phone number on a separate device isn't enough, you also need to enter the pin. (Not on by default though.)
>You can have your phone compromised (especially when I know your phone number, Signal I’m looking at you) or be subject to other means of attacks, exposing everything.
Knowing someone's phone number doesn't automatically let you compromise their device. This is such a ridiculous argument.
>I would rather know that this app is not secure so I don’t share anything important, while keeping secure communication to other means.
This is nirvana fallacy. It's essentially saying "We should not talk about Telegram lying about its security, when in reality nothing is 100% secure". Yeah, nothing is, there's always an attack. That doesn't contribute anything of interest to the topic, it just tries to kill the criticism. And I'm saying this as someone who has worked on this exact topic for ten years: https://github.com/maqp/tfc
> Knowing someone's phone number doesn't automatically
One way or another, phone numbers are like home addresses in the digital world. Once exposed, it’s just a matter of time and resources dedicated to that. Not to mention, sometimes it’s just needed to cross over the identity, that’s it.
> This is a nirvana fallacy. It's essentially saying
I didn’t say that. As I mentioned in the other comment to you, some or a lot of people just don’t care about security, and as long as this info is known, it should be treated just like any social media.
Great project with TFC, I never heard of it, but it looks interesting. I would definitely give it a try! I have a question though: does your project require a phone number? If not, why? And would you recommend Signal to anyone who is after security, privacy, and anonymity?
>If not, why?
Because that's the trade-off you make when you want high entropy unique usernames to prevent enumeration attacks. They become long and random. There's still a "phone number". It just looks something like 4sci35xrhp2d45gbm3qpta7ogfedonuw2mucmc36jxemucd7fmgzj3ad. You know that string and you can make a computer somewhere in the world accept some GET requests. Who knows if Flask, or whatever is part of the stack, has zero-click vulnerabilities.
And yes obviously I would recommend Signal to anyone who wants content privacy. Since Signal offers only narrow by-policy metadata privacy (unless you're on burner hardware), I'd ask them if they wanted metadata privacy, and if so, I'd point them to the direction of Cwtch https://cwtch.im/. I wouldn't recommend TFC unless endpoint compromise was part of their threat model. It's complicated and nuanced in the deep end of the pool.