Nostr

Every Nostr event carries an id, the author's public key, a timestamp, a kind, tags, content, and a signature. Signatures are Schnorr signatures on the secp256k1 curve, as NIP-01 specifies.

Clients connect to relays over WebSockets, publish events, and subscribe with filters. Relays do not talk to each other by default, so clients usually publish to and read from several. Extensions are written up as NIPs (Nostr Implementation Possibilities).

Because identity is a key and relays are interchangeable, no single operator controls who can publish, and anyone can run a relay. That makes Nostr a useful internet path for apps that want to avoid depending on one central server.

Relays still see metadata, such as which keys publish, when, and how much, even when content is encrypted. And Nostr needs an internet connection to reach relays.

Offline Protocol can use Nostr as an opt-in transport: when a device can reach Nostr relays, the SDK carries messages through them and seals envelopes by default, so relay operators cannot read the content. It is an additional network path, not a substitute for a local radio when there is no network.

Configure relays suited to your deployment rather than an example public relay; a relay still observes subscriptions, timing, and volume. See the docs on Reticulum and Nostr and mesh networking.