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The Rust crypto core runs in the browser

The encryption design from the security docs is now real code. It’s one Rust library that every Octa Pass app will share. The web vault runs it as WebAssembly inside a Web Worker, so keys never touch the page’s JavaScript.

What’s built

  • Key derivation: your master password goes through Argon2id (64 MiB, 3 iterations) and is combined with your 128-bit Secret Key into the key that unlocks your account. In WebAssembly an unlock takes about 0.2 seconds on a 2019 laptop.
  • Encryption: every ciphertext is XChaCha20-Poly1305, tagged with a key id and bound to its place (account, vault, item, overview or details), so the server can’t move encrypted data around.
  • Login without sending your password: sign-up and sign-in use OPAQUE. Re-authentication before deleting your account uses the same protocol.
  • Device unlock: the web vault can wrap your account key with a passkey’s PRF secret, so Touch ID, Windows Hello or your device passcode can unlock it. That key never leaves the browser.
  • Recovery: a 256-bit recovery code, 11 groups of 5 characters with a built-in typo check, can unlock your account if you forget your password.
  • Tools that run on your device: TOTP codes (including Google Authenticator exports), a password and passphrase generator using the EFF wordlist, strength estimation, and the k-anonymity check for breached passwords.

For developers

The formats are documented byte by byte in crates/octapass-core/README.md, and the web worker API in crates/octapass-wasm/README.md. Deterministic test vectors for every construction are in crates/octapass-core/tests/vectors, so other implementations can check that they interoperate.