Hong Kong Protesters Using Mesh Messaging App China Can’t Block: Usage Up 3685% – Slashdot:

An anonymous reader quotes Forbes: How do you communicate when the government censors the internet? With a peer-to-peer mesh broadcasting network that doesn’t use the internet.

That’s exactly what Hong Kong pro-democracy protesters are doing now, thanks to San Francisco startup Bridgefy’s Bluetooth-based messaging app. The protesters can communicate with each other — and the public — using no persistent managed network…

Too bad that Bridgefy is proprietary software. Luckyly there are free-as-in-freedom alternatives: the first entry is Briar:

Briar is a messaging app designed for activists, journalists, and anyone else who needs a safe, easy and robust way to communicate. Unlike traditional messaging tools such as email, Twitter or Telegram, Briar doesn’t rely on a central server – messages are synchronized directly between the users’ devices. If the Internet’s down, Briar can sync via Bluetooth or Wi-Fi, keeping the information flowing in a crisis. If the Internet’s up, Briar can sync via the Tor network, protecting users and their relationships from surveillance

It has a nice website, it’s available on both Google Play “walled garden” and in the free-as-in-freedome F-Droid repository: