# lastsignal

> Self-hosted dead man's switch that sends encrypted messages to recipients when you stop checking in via email. Zero-knowledge architecture with client-side encryption.

- **Category:** Security
- **Licence:** MIT
- **Open source:** oss
- **Languages:** Ruby, HTML
- **Platforms:** Docker Compose, Linux
- **Tags:** SQLite, Privacy, Email, Encryption, End To End Encryption, Cryptography, Argon2id, Privacy Tools, Zero Knowledge, Open Source, Ruby On Rails, Ruby, Self Hosted, Xchacha20 poly1305, E2ee, Digital Legacy, Dead Man Switch

## Description

LastSignal lets you write encrypted messages for recipients and proves you're alive through periodic email check-ins. If check-ins stop, messages are delivered automatically. All encryption happens in the browser using Argon2id (256 MB) for key derivation and XChaCha20-Poly1305 for message encryption — the server cannot access plaintext or private keys. Features include trusted contacts who can delay delivery, per-recipient delivery delays, recovery codes for emergency stop, and a complete audit trail. It runs as a Ruby on Rails 8 application with SQLite, deployed via Docker Compose or Kamal. No hosted service exists; users must provide their own SMTP provider for email delivery. The project is MIT-licensed with no paid tiers.

## Links

- [Homepage](https://github.com/giovantenne/lastsignal)
- [Website](https://lastsignal.app)
- [Documentation](https://github.com/giovantenne/lastsignal)
- [Security Model](https://lastsignal.app/security/)
- [Disclaimer](https://github.com/giovantenne/lastsignal/blob/master/DISCLAIMER.md)

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Source: https://selfhost.directory/project/lastsignal