From U2F to FIDO2: The Future of Secure, Passwordless Authentication

FIDO (Fast Identity Online) does not only consist of U2F (Universal 2nd Factor). In fact, the FIDO Alliance has developed multiple authentication standards, with U2F being just one of them. The FIDO ecosystem has evolved from U2F, which is primarily used for two-factor authentication (2FA), to the more advanced FIDO2, which supports passwordless authentication and multi-factor authentication (MFA).

The Two Main FIDO Standards:

1. FIDO U2F (Universal 2nd Factor):

• Released: FIDO U2F was introduced in 2014.
• Primary Use: U2F is designed for two-factor authentication (2FA). It works by requiring users to authenticate using their traditional password (something they know) and then confirming their identity through a hardware security key (something they have).
• Key Features:
  • U2F is mainly used to enhance security by adding a second layer of authentication to password-based logins.
  • It is widely compatible with services that support 2FA, such as Google, Facebook, Dropbox, etc.
  • U2F uses the CTAP1 protocol (Client to Authenticator Protocol 1), allowing devices to communicate with security keys.
  • Limitation: U2F cannot support passwordless login. A password is still required as the first factor of authentication.

2. FIDO2:

• Released: FIDO2 was introduced in 2018 as an evolution of U2F, enabling passwordless authentication.
• Components:
  • WebAuthn (Web Authentication API): A W3C standardized API that allows websites and applications to interact with authentication devices, such as security keys or biometrics, for secure login.
  • CTAP2 (Client to Authenticator Protocol 2): The protocol that supports additional authentication methods, including PIN and biometric authentication, enabling secure, passwordless authentication.
• Primary Use: FIDO2 allows for passwordless authentication, where users can log in without needing a password. Instead, they can use biometrics (fingerprint or face recognition) or a hardware security key.
• Key Features:
  • Passwordless login: Users can log in using just a security key or biometric authentication.
  • Multi-factor authentication (MFA): FIDO2 supports both passwordless authentication and MFA, combining multiple authentication factors for greater security.
  • Cross-platform compatibility: FIDO2 works across browsers, mobile devices, and desktops, allowing seamless authentication across platforms.
  • Backward compatibility: FIDO2 is backward compatible with U2F, meaning that many services that support U2F can also use FIDO2 keys.

Key Differences Between U2F and FIDO2:

In Summary:

• FIDO U2F: An early form of the FIDO standard, designed specifically for adding a second factor (usually a security key) to password-based logins for 2FA.
• FIDO2: A more advanced standard that builds on U2F, offering passwordless authentication as well as the ability to support multi-factor authentication (MFA). It provides greater flexibility and security in modern authentication scenarios.

So, FIDO is not just about U2F; it also includes the broader FIDO2 standard, which allows for more secure, flexible, and password-free authentication. If you're looking for modern and convenient passwordless login, FIDO2 is the more comprehensive solution.