Briar: Peer-to-Peer Encrypted Messaging

Briar: Peer-to-Peer Encrypted Messaging
briarproject.org

That seems like a pretty big assumption. From what i understand there already exists deployment of wifi hot spots to track people (both for advertising purposes and for spying purposes) to the extent that phone providers started radomizing MAC addresses.

The downside is of course, you need to keep the endpoint powered on when you want to be reachable so it will increase the battery drain on your phone.

Note: There's also a desktop client if that's easier to keep online https://briarproject.org/download-briar-desktop/

One extremely important thing Briar is doing, is it's using the P2P as means to host alternative social interaction formats, like forums and blogs. Similar to Signal/WhatsApp stories (which is somewhat similar to microblogs/FB wall), it's a way to indirectly share information. You could pretty much emulate any social media platform on top of E2EE protocol with ~zero infrastructure cost and without having to worry about data mining. I'd argue what Briar's innovating on here is one of the most important aspects in what's left for secure messaging.

Finally a small caveat: Briar will share your Bluetooth MAC address with all peers so it can automatically use that when you're in close proximity with your peer. Thus sharing your Briar ID publicly is not a good idea for two reasons:

1) major global adversaries may have access to the leaking Bluetooth MAC (e.g. if Google aggregates it) which can deanonymize your account. This also allows slightly technical person to confirm identity of briar account if they suspect it's you (a bit wonky threat model but still).

2) it ties everything you do across your accounts on same device together, so there's strong linkability even if you rotate the identity key by reinstalling the app.

Briar is pretty clear about this in it's FAQ, but it's still not very well known although it definitely should be.

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That being said, if you want similar Onion Service based communication with no such linkability, there's https://cwtch.im/ which is a fantastic project.

There's also https://www.ricochetrefresh.net/

Both are spiritual successors to John Brooks' `Ricochet` application which pioneered the whole Onion Service based instant messaging in 2014.

You can also chat and share files (among other things) with https://onionshare.org/

(And finally, you can get remote exfiltration security for keys/plaintexts with TFC https://github.com/maqp/tfc (my personal work), at the cost of losing some features like message forwarding etc that the architecture prevents you from doing.)

I'm not sure if this really works, but if it's a short message and you periodically check the server if there's a reply and the service responds with short reply, the Tor cell padding (to 500 bytes IIRC) would make it harder to observe metadata about when communication takes place. This all of course goes out the window if it's a large packet that requires multiple cells, or if it's the client that just POSTs the outgoing messages to the server over an established connection.