Yubico Authenticator is an open-source application designed to manage YubiKey security devices and access hardware-protected authentication credentials. It enables users to generate and retrieve one-time passwords stored securely on compatible YubiKeys. The application supports Windows, macOS, Linux, and Android, providing a consistent authentication experience across devices. Users can configure security settings, manage passkeys, and administer authentication credentials through an intuitive interface. It also supports FIDO authentication, PIV certificate management, and YubiKey slot configuration. Sensitive authentication secrets remain on the physical security key rather than being stored directly on the computer or smartphone. With USB and NFC compatibility, the application provides a portable solution for strengthening account security without requiring an internet connection.