Show HN: Seal – letters and passwords that open for your family after you die

Category: security

Tags: ios, e2ee, passkeys, shamir-secret-sharing, posthumous, swiftui, no-backend, cryptography

Score: 7.5/10 (Innovation: 7, Technical: 8, Documentation: 9, Utility: 6)

Seal is an iOS app that lets you leave encrypted letters, passwords, and files for loved ones, released only after you go silent past a configurable threshold. It combines passkeys, Secure Enclave hardware keys, X25519+ML-KEM hybrid wrapping, Shamir secret sharing, and CloudKit with no backend server, plus an independent Python capsule verifier. It is a thoughtfully engineered take on a genuinely hard problem (posthumous secret release) that is only novel in its packaging rather than its cryptography.

Target audience: privacy-conscious iOS users, security engineers, developers interested in applied cryptography and digital legacy planning

Repository: https://github.com/jasonepage/Seal · Swift · MPL-2.0 · 1 stars

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