Glossary

WebAuthn

Web Authentication

Web Authentication, the W3C API with which browsers and platforms create and use public-key credentials scoped to a relying party; Level 3 became a W3C Recommendation in August 2026. The server sends a random challenge, the authenticator signs it with a private key bound to the site, and the server verifies the signature, the origin and the user-verification flags.

Defined in: W3C Web Authentication Level 3

Covered in

Guide

Passkeys and MFA: WebAuthn enrollment, sign-in and replacement

Register, verify and replace passkeys with WebAuthn so phishing resistance survives the account’s whole lifecycle, and map passkeys and other MFA methods to the NIST SP 800-63B-4 assurance levels.