Briar: Peer-to-Peer Encrypted Messaging

Briar, for when security and deliverability of your messages aren't really the point...

The directory services are the equivalent of DNS.

The role of Tor is it facilitates anonymous, end-to-end encrypted connection between client and server, each messaging app is both a client (or a set of clients) and a server (a Tor Onion Service) that talk to each other through the Tor network. This way the traffic never exists the Tor network*.

Tor Project has an excellent new article about Onion Services at https://community.torproject.org/onion-services/overview/

The laptop/phone is the client, and Secure Drop is the server. With Briar the client-side Tor socket connects to the messaging app instead of browser, and on server side the socket again connects to the messaging app instead of web server. Whether messages flow from client to server (via POST request) or server to client (GET request) is doesn't really matter. The architecture where each user runs both server and client makes it effectively peer-to-peer.

Because messaging apps are these days expected to be always online, you pretty much need to have the server and client (and thus the app) always running.

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*This is in contrast to Tor Messenger that, while it defaulted to Tor, used exit nodes unless the XMPP server was also a Tor Onion Service. While with Tor Messenger you were anonymous, XMPP server was usually not self-hosted thus a third party might have aggregated some metadata about when conversations between two accounts took place etc.

Things used to be even worse before Tor Messenger. With Pidgin it was possible to forget to configure Tor (unless you used XMPP Onion Service), and even worse, forget to enable OTR end-to-end encryption for every session, and if that happened the content could easily deanonymize you.

With Onion Service messaging, provided you verified the authenticity of the V3 onion address (or E2EE protocol's key fingerprint), you can be rest assured

1) connection is always E2EE

2) always inside Tor with no possibility to F up by connecting over 'clearnet'

3) no third party has access to communications metadata

Just wanna say this app saved my family and I when we went on a cruise. Normally, we would had had to pay to use the chat service via the ship's paid-only Wi-Fi (since we get no phone reception on the seas). Without needing to pay for the Wi-Fi, we were all able to use Briar to communicate whilst connected to the network, which made coordinating and finding each other on the ship way easier. It was great and worked really well. So thanks, Briar!

My wife and I use Briar for household communication because of subsidiarity rather than any direct privacy concerns. Out of all the messenger projects that we've tried, Briar actually works for local communication. It's actually instant messaging without any client hiccups or latency (looking at you, Signal). We've tried a ton of other options, but we keep ending up back at Briar.

There are points of UX friction in the name of good opsec that are inconvenient but totally understandable given the project goals. The big ones being that you have to manually login after any reboots and notifications are intentionally sparse, so good luck using a smartwatch for reading or replying. Otherwise, the forums and blogs are great for managing household projects, IM is a dream, and as a bonus, anyone willing to install and use it probably has a large enough values overlap that we can use it as a social pre-filter for close friends.

The only other option that has come even remotely close to being as functional as Briar is DeltaChat. The only issue that stops us from using DeltaChat (or email in general) is that we both have email hosting in Europe while we live in the US, so neither of us, being frugal in principal, wants to send information to Europe and back in order to tell the person 100 ft away to come help bring in the groceries.

I understand why you don't think Briar has good deliverability.

But what makes you think that the security of Briar messages is suspect?