WebAuthnFIDO2standardit

WebAuthn and FIDO2 are standards that enable passwordless, phishing-resistant authentication on the web. WebAuthn is a W3C API that lets web applications interact with user authenticators. FIDO2 is an alliance between FIDO and W3C that combines WebAuthn with the Client-to-Authenticator Protocol (CTAP), enabling external authenticators to communicate with a user’s device.

Registration flow: the relying party sends a challenge; the browser forwards it to the authenticator, which creates a new public-private key pair and stores the private key. The public key and metadata are kept by the relying party. For authentication, the challenge is signed with the private key, and the signature is verified using the public key. Authenticators can be platform-based or roaming.

Attestation and privacy: authenticators may provide attestation data about their platform. Privacy controls allow suppressing or limiting this data. WebAuthn supports user verification options (required, preferred, or discouraged) for biometric or PIN input. The design emphasizes origin binding, reducing phishing.

Adoption and ecosystem: WebAuthn is supported by major browsers (Chrome, Firefox, Edge, Safari) and is implemented by many platforms. Relying parties include large websites and services; TLS encryption (HTTPS) is required. Passkeys and cloud backups have expanded cross-device usability while preserving cryptographic security.

Limitations and considerations: recovery after loss, credential revocation, and interoperability with legacy passwords remain considerations. The standard continues to evolve to improve usability and deployment.