FIDO (Fast IDentity Online) is an open standard for easy and secure authentication.
FIDO specifications and certifications enable an interoperable ecosystem of hardware-, mobile- and biometric-based authenticators which can be used with many apps and websites.
For more information, see the FIDO Alliance website.
You can find out here how FIDO operates.
Two standards were developed by the FIDO Alliance by 2014: U2F and UAF.
Quelle: FIDO Alliance
Successor of the two protocols is FIDO2.