this post was submitted on 06 Mar 2024
127 points (98.5% liked)
Privacy
4014 readers
11 users here now
A community for Lemmy users interested in privacy
Rules:
- Be civil
- No spam posting
- Keep posts on-topic
- No trolling
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Don't get me wrong. I like the signal foundation. They do great work. I'm just hesitant to claim that usernames are in anonymous way to talk to people on the internet.
If your model of signal is just I can communicate and encrypted with people I already know and who know me. Everything's fine. Nothing about the server compromises that. But when you introduce can I talk people anonymously, the model doesn't support that. Because the server has the capability to deanonymize.
If nothing else, somebody could simply brute force all the phone numbers, until their named contact shows up.
I just did some minor testing, right now, if you have a username that you want to post on the internet, like embarrassing_contact.01, like for political dissidents organizing, alternative lifestyle organization, disclosing sensitive information etc. if you already have the contact on your phone, but you try to send a message to the username. Signal will tell you oh it's the same person you already have this contact. So right there is a proof of concept of deanonymizing people
If that is your threat model you can put your phone number privacy to no one. Then I can't see you use Signal even if I have your contact with your phone number saved and adding you with your username won't show you as my phone contact with the same phone number.
That's good feedback, I wasn't aware it existed. Thank you