End-to-end encryption

Only the people in a conversation can read it. Not Pigeon, and not the network that carries it.

How it works

1. Sealed on your device. Every message is encrypted with MLS (RFC 9420), the open standard for group messaging, with keys only the people in the conversation hold.
2. Sealed again. It then goes into a second, outer envelope (HPKE, RFC 9180, with a hybrid post-quantum key exchange), so the network sees no group, sender or recipient.
3. Opened by them. The people in the conversation collect it and open it. Once it's delivered, the copies on the network are deleted.

Keys

Your account is a set of keys made on your computer and backed by your seed phrase. Group keys change as members come and go, so someone who leaves can't read what follows, and a key stolen today doesn't open older messages.

What the network sees

Sealed envelopes, their size and the time they arrive, and your IP address while your device is connected. The IP address isn't written to disk or to logs. The privacy policy lists everything, with how long each thing is kept.

What encryption can't hide

• Someone able to watch a lot of internet traffic could use addresses and timing to guess who is talking to whom.
• Anyone in a conversation can share what's said in it.
• A device that is unlocked and in someone else's hands can be read. See devices.
• Pigeon is an alpha and hasn't had an independent security audit.