The universal 2nd factor (U2F) is an open protocol for reinforcing 2FA with specialized NFC and USB devices. Google and Yubico developed it with NXP Semiconductors to provide an additional security layer against man-in-the-middle and phishing attacks.

Examples of U2F

Advantages and Disadvantages of U2F



Using U2F

Difference between FIDO U2F and FIDO2

FIDO2 was developed by FIDO Alliance to replace U2F with passwordless authentication as the key feature. The new authentication standard enabled users to log in using the FIDO2 security key or biometric data such as face ID or fingerprint.

FIDO2 has become increasingly popular due to its backward compatibility with FIDO U2F. It is now being adopted as the new 2FA and passwordless authentication.

U2F History

U2F first gained attention in 2012 after tech blogs reported that Google was using key fobs for authentication. While the tools weren’t widely used in the industry at the time, the excitement and attention were building up already.

In 2014, the partnership of Google, Yubico, and NXP Semiconductors proposed the standards.  Eventually, the open-source standards fell under the jurisdiction of the FIDO Alliance, which continues to maintain and administer it today.