Pulsar: Private Nostr Chat App That Protects Metadata
Pulsar is an encrypted chat app that masks your metadata. It works by sending fixed-length, fixed-frequency messages over the nostr messaging network.
- "Introducing Pulsar a private nostr chat app that protects your metadata."
- "Pulsar was originally prototyped by supertestnet and I joined him a few weeks ago to build out the frontend and add all of the basic features to reach an MVP."
- "Pulsar is still very much in early alpha phase, the code is a little messy, but it works as expected. If people like this approach I plan on rebuilding Pulsar as a native app, but for now it will live as a simple web app."
- "Personally my final ideal state for Pulsar would be a Signal like experience with the same privacy guarantees but without the need to provide a phone number."
How it works
- Each chat instance is encrypted with a shared secret that also acts as an invite for others to join the chat group and decrypt the messages;
- Each real keypair of the participants in the chat instance is wrapped in an ephemeral keypair (which is what is broadcasted to the relays);
- All messages are encrypted by default with the shared secret using the ephemeral keypairs;
- A fresh ephemeral keypair is also created for each message;
- All messages are padded with garbage data to give them each the same length;
- Additionally a padded / encrypted message is posted every 3 seconds while the instance is open (this is the pulse) which prevents outside observers from identifying the real messages AND when real messages are posted;
- Note that Pulsar MUST be used with Tor or alongside a VPN or you will leak your IP address.
