According to NIST Special Publication DRAFT 800-63-B4, a phishing-resistant authenticator offers “the ability of the authentication protocol to detect and prevent disclosure of authentication secrets and valid authenticator outputs to an impostor relying party without reliance on the vigilance of the subscriber.” Two examples of phishing-resistant authenticators are PIV cards for US Federal employees and FIDO authenticators paired with W3C’s Web Authentication API for the private sector.