Proton Authenticator is a free, open-source two-factor authentication app designed for enhanced security on Android devices. It allows users to generate and store one-time passwords (TOTP) securely, ensuring that account protection is accessible even offline. The app is particularly notable for its end-to-end encryption and adherence to Swiss privacy laws, making it a reliable choice for privacy-conscious users.

Key features include the ability to sync 2FA codes across multiple devices, automatic backups, and easy import/export capabilities with other authentication apps. Users can also enhance security by using biometrics or a PIN code. With its ad-free experience and no requirement for a Proton account, Proton Authenticator stands out as a user-friendly option for managing digital security.