TouchBridge

TouchBridge lets a Mac authenticate actions such as sudo, screen unlock, or App Store purchases by using the fingerprint or face sensor on a paired mobile device instead of a built‑in Touch ID sensor. The daemon runs on macOS 13+ and communicates with iPhone, Android, Apple Watch, Wear OS, or any browser‑based client, prompting the user to approve the request on the phone or watch. Authentication data is signed by the device’s secure enclave or keystore and transmitted over encrypted Bluetooth (ECDH + AES‑256‑GCM) or a local‑network HTTP token for browser use, with no cloud services involved.

The software is open‑source, MIT‑licensed, and available as a free Homebrew cask or from source. Installation sets up a PAM module that redirects password prompts to the mobile device, and the companion apps on the phones handle the biometric verification. Users can uninstall at any time with a provided script.

TouchBridge targets macOS users who lack a built‑in fingerprint sensor or who wish to avoid purchasing additional hardware such as a Magic Keyboard with Touch ID. It provides a cost‑free, cross‑platform biometric authentication layer while keeping the verification process local and encrypted.