Universal 2nd Factor
Universal 2nd Factor (U2F) is an open authentication standard that strengthens and simplifies two-factor authentication using specialized USB or NFC devices based on similar security technology found in smart cards. While initially developed by Google and Yubico, with contribution from NXP Semiconductors, the standard is now hosted by the FIDO Alliance.
Chrome, Firefox and Opera are currently the only browsers supporting U2F natively. Microsoft is working on FIDO 2.0 support for Windows 10 and the Edge browser, but has not announced any plans to include U2F support. Mozilla has integrated it into Firefox v.57.