| Hi HN, I built LastSignal because I was uncomfortable trusting a third party with extremely sensitive information (final messages, recovery instructions, etc.). LastSignal is a self-hosted dead man's switch: you prepare encrypted messages that are automatically delivered to chosen recipients if you stop responding to periodic check-ins. Security-wise, the server is treated as untrusted by design: - messages are encrypted client-side - the server never sees plaintext - the operator cannot decrypt stored data I've documented the security model, threat assumptions, and known limitations here: https://lastsignal.app/security/ Source code: https://github.com/giovantenne/lastsignal This is an early but usable version. I'm especially interested in feedback on the threat model, edge cases, and assumptions around liveness and delivery. Happy to answer questions. |