What Is FIDO2 Authentication?

FIDO2 authentication is a passwordless login method that uses public-key cryptography to securely verify a user’s identity. Developed by the FIDO Alliance and W3C, it offers a safer, more convenient alternative to traditional passwords.

The term FIDO in FIDO2 stands for Fast Identity Online. The “2” indicates the second generation of the standard.

Types of FIDO2 Authentication:

Hardware-Based Authentication: Uses dedicated physical devices to verify identity.

  • Security Keys: External devices that connect via USB, NFC, or Bluetooth. Examples are the YubiKey and the Google Titan security key.

  • Smart Cards: Cards with embedded security chips.

Platform-Based Authentication: Integrated into smartphones and computers.

Examples: Apple’s Face ID and Touch ID (Secure Enclave), Windows Hello (TPM), and Android biometric login.

How FIDO2 Authentication Works:

When registering with a service, FIDO2 generates a public-private key pair:

  • Private Key: Stays securely on the user’s device.
  • Public Key: Stored by the service.

During login, the service sends a challenge. The user’s device signs it with the private key, and the service verifies it with the public key—proving identity without sharing passwords.

Benefits of FIDO2 Authentication:

  • Phishing-Resistant: Authentication is tied to the service’s domain, blocking fake websites (e.g. if an attacker presents a fake website to try to capture user credentials)
  • No Shared Secrets: Private keys never leave the user’s device.
  • Fast and Easy: Supports biometrics, such as fingerprint or facial recognition.
  • Multi-Factor Support: Combines device-based authentication with biometrics or PINs.