The Fast Identity Online (FIDO) framework aims to support a variety of authentication technologies to replace passwords, including biometrics, security tokens, and smart cards. It uses public-key cryptography where the user's device generates a key pair during registration and then signs a challenge from the server for login. There are two main protocols - Universal Authentication Framework (UAF) which allows authentication through local actions like fingerprints, and U2F which provides a second factor for login through a security key. FIDO has advantages like reducing password complexity and recovery procedures, but also has disadvantages like requiring compatible hardware and potential to forget authentication devices.