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 a simple nostr group chat app that aims to follow best practices to secure all of the data and metadata associated with a chat instance.
Here is how pulsar protects your privacy:
- 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
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. 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.
Thanks for reading and please provide any feedback you have or issues you experience while using Pulsar.
Onwards!