FIDO supports a full range of authentication technologies, including biometrics such as fingerprint and iris scanners, voice and facial recognition, as well as existing solutions and communications standards, such as Trusted Platform Modules (TPM), USB security tokens, embedded Secure Elements (eSE), smart cards, and near field communication (NFC).[2] The USB security token device may be used to authenticate using a simple password (e.g. four-digit PIN) or by pressing a button.