"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.