libfido2 is an open source library for the FIDO2 protocol. FIDO2 is an open
authentication standard which consists of the W3C Web Authentication specification
(WebAuthn API), and the Client to Authentication Protocol (CTAP). CTAP is an application
layer protocol used for communication between a client (browser) or a platform
(operating system) with an external authentication device (for example the Yubico Security Key).