Briar: "Censorship-resistant peer-to-peer messaging that bypasses centralized servers. Connect via Bluetooth, Wi-Fi or Tor, with privacy built-in." https://briarproject.org/
Would be cool to have bluetooth & wifi sync on native Nostr apps. Would be useful in offline situations and countries where the internet is censored.
Discussion
Meshtastic is interesting, but apps that work on every phone over bluetooth and wifi would have better reach, and simpler setup
Or better yet over encrypted mesh network Wi-Fi. Bluetooth is pretty insecure.
