IDmelon Authenticator by IDmelon Technologies Inc. is a FIDO-certified mobile application that transforms smartphones into FIDO2 USB security keys, enabling passwordless authentication. It allows users to store and manage passkeys on their smartphones for secure logins to accounts, web services, and applications on PCs, eliminating the need for traditional passwords. The app supports both iOS and Android platforms, providing broad device coverage and cross-platform synchronization. IDmelon Authenticator can be used in conjunction with IDmelon Reader or through pairing with a PC to provide a tap-and-login experience. It supports various authentication methods, including biometrics and device PINs, and implements strong security measures such as end-to-end encryption and FIDO standards based on public key cryptography.