I’ve been looking into Briar messenger app but it doesn’t seem to have much documentation.
Being a decentralized app, they say that communication between devices can be done over a wifi lan, bluetooth or over Tor/Internet.
But I still don’t understand how devices find each other.
This doesnt really answer your question, but years ago I wrote an instant messenger app that works over Bluetooth. Your post just reminded me of that. I also wrote my bachelor thesis about that project (linked in the readme).
I’m guessing that you and your contacts exchange MAC and Onion addresses. Then Briar looks for that MAC address via WiFi/Bluetooth or an Onion address on Tor.
I’ve watched a video where Torsten Grote explains some of it. In fact you’re right when you say it uses the onion address on Tor (I also had assumed that). But he doesn’t explain how the contacts exchange work on a local LAN. I’m not sure it uses the MAC addresses because those are not reliable in the sense that they can be easily spoofed. But maybe I’m wrong because in the end what counts is if the device know the private key or not. Here’s the video: https://media.ccc.de/v/34c3-8937-briar
Just tried it with my brother. Briar generates a random URL-like string such as “briar://7f2g83f7832hgb87f3b…” on your device which you share with the person you want to be in contact with, and they send you their string. Once you’ve both pasted each other’s strings in the proper form field it connects and you can start messaging each other.
ct with, and they send you their string. Once you’ve b
that “random” string is in fact the Tor hidden service address.
I always assumed it was a matter of open ports, or just devices swapping MAC addresses, then they send information in the normal way over those channels.
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