Universal 2nd Factor (U2F)
security · authentication
A hardware-backed second-factor standard that uses security keys for phishing-resistant account login.
- Also known as
- Security Key
U2F uses a physical security key to approve logins after a password is entered. The key signs a challenge for the exact website origin, which makes fake login pages much harder to use successfully.
Modern WebAuthn and FIDO2 build on the same family of standards and can support passkeys or passwordless flows. For crypto users, hardware security keys are most useful for protecting exchange, email, password manager, and cloud backup accounts.
Related terms
Two-Factor Authentication (2FA)
→An account security method requiring two different proof factors, such as a password plus an app code or hardware key.
security · basics
Hardware wallet
→A physical signing device that keeps private keys isolated while approving cryptocurrency transactions.
wallet · security
Private Key
→Secret cryptographic material used to produce signatures or other authorization proofs.
cryptography · security · wallet