Keygrain

Deterministic password generator with encrypted sync. Your master password never leaves your device.

Keygrain is a deterministic password generator. Instead of storing generated passwords in a vault, it derives them on-the-fly from your master secret and the site name. The same input s always produce the same output, and derived passwords are not stored. The extension may retain local service configuration, account/device state, and encrypted service data. HOW IT WORKS: • Enter your master secret and email • Get a unique password for any site • Copy to clipboard or autofill directly FEATURES: • Deterministic — same inputs = same password, every time • TOTP — derive authenticator codes from your master secret (no separate app needed) • SSH keys — generate deterministic Ed25519 SSH keys • HD wallets — derive BIP-39 mnemonic seeds for cryptocurrency wallets • Encrypted sync — optionally sync your site list across devices (encrypted service data; the master secret and derived passwords are not sent to the sync server) • Autofill — fills password fields with one click or Ctrl+Shift+Y • Per-site customization — adjust length, symbols, and counter • Visual verification — colored fingerprint confirms your secret is correct • Auto-lock — master secret cleared from memory after inactivity • Context menu — right-click any password field to fill • No derived-password storage — generated passwords are recomputed; local service configuration, account/device state, and encrypted service data may remain on the device • Optional PIN unlock — may retain an encrypted local copy of the master secret SECURITY: • HMAC-SHA256 cryptographic derivation with Argon2id key strengthening • Master secret never leaves your browser; derived passwords are never sent to the sync server • Sync data encrypted locally before transmission — server cannot decrypt • No analytics, no tracking, no cookies • Open source: https://github.com/iheb-eddine/keygrain PRIVACY: • Zero plaintext data collection • Sync transmits only encrypted blobs • Privacy policy: https://keygrain.com/privacy.html