密语

A private messenger meant only for people who already know each other. Messages are encrypted on your device and decrypted only on theirs; the relay server handles nothing but ciphertext and deletes it on delivery. Even group chats don't exist on the server — members forward each message to one another, individually encrypted. The local chat database is fully encrypted, cached attachments stay encrypted, and there is an app lock, screenshot blocking and disappearing messages. On the same Wi-Fi, two devices find each other and talk directly with no server at all; voice and video calls go peer-to-peer and fall back to a built-in relay, still end-to-end encrypted. Moving to a new phone takes one passphrase-encrypted backup. The crypto core is written in Rust (the Olm double ratchet via Matrix's vodozemac), the UI in Flutter — one codebase for Android and Windows — and the server in Go. It went from kickoff to both platforms passing hands-on tests in two days, designed by me and built together with AI.