The YubiKey physical security key offers superior security by combining hardware-based authentication and public key cryptography to effectively defend against phishing attacks and eliminate account takeovers. It offers multi-protocol support including FIDO2, Yubico OTP, OATH HOTP, U2F, PIV, and Open PGP. Users have the broadest options for strong authentication including not only two-factor authentication, but also support for single factor passwordless login and multi-factor authentication in conjunction with user touch and PIN.