Seal

Seal is an iOS app for writing sealed envelopes—encrypted bundles containing letters, photos, voice messages, and sensitive information like passwords and seed phrases—intended to reach trusted people after your death. Each envelope is encrypted on your phone with no backend server, and opens only after months of inactivity plus weeks of daily warnings. You choose a few trusted contacts in person, each receiving a piece of a key that alone reveals nothing.

The app is open source under MPL 2.0, with all code publicly available for inspection. The maker says it was built with Claude. Seal stores encrypted envelopes in Apple's iCloud under its own container, never on personal iCloud storage, and the opening record can be verified with an independent Python script. The project has not undergone third-party security audit.