Passkeys / FIDO2 / WebAuthn

Passwordless authentication based on public-key cryptography, delivered through WebAuthn (W3C) and CTAP (FIDO).

Overview

Passkeys implement passwordless login using public-key cryptography. Users authenticate with a device-bound credential and local user verification (biometric or PIN), via the WebAuthn API and CTAP protocols.

How it works

  1. Registration: Site asks for a new credential via WebAuthn; an authenticator creates a key pair and returns a public key + attestation.
  2. Authentication: Site sends a challenge. Authenticator signs it with the private key after local user verification.
  3. Device portability: Platform sync or roaming authenticators (security keys) enable use across devices in line with vendor policies.

Common use cases

  • Consumer sign-in replacing passwords
  • Workforce phishing-resistant MFA
  • Step-up auth for high-risk transactions
  • Zero-trust endpoint access
  • Privileged-account and administrative access

Strengths and limitations

Strengths: Phishing resistance; no shared secrets; fast UX.
Limitations: Cross-ecosystem portability; attestation policy; account recovery patterns.

Key terms

  • WebAuthn: W3C API for creating/using credentials.
  • CTAP: FIDO protocol between client and authenticator.
  • Attestation: Evidence about the authenticator model/security.

Current market signal

Passkeys and FIDO credentials are expanding from consumer sign-in into national identity and enterprise authentication. Singpass adoption and Microsoft's Entra migration timeline show large identity platforms moving phishing-resistant credentials from an option toward a default.

References

Vendors using Passkeys / FIDO2 / WebAuthn

Latest Data Cards

  • Data Card

    Nexiden sues Ping Identity over mobile authentication patents

    2026-08-21CC-BY-4.0digital-idpasskeys-webauthn

    Nexiden filed a patent infringement suit against Ping Identity in Texas federal court over two patents covering secure mobile device registration and session-based authentication.

    • The asserted patents are US 9,521,548 and US 10,592,872, covering on-device private keys paired with local biometric authentication.
    • Nexiden says licensing approaches in March 2023 and September 2024 did not succeed; the target is the PingID app.
    • Nexiden seeks an injunction plus damages for past and ongoing infringement.
  • Data Card

    Yubico ships YubiKey firmware 5.8 with hardware-backed signing

    2026-07-21CC-BY-4.0passkeys-webauthn

    Yubico released YubiKey firmware version 5.8, adding CTAP 2.3 support and a preview of the WebAuthn signing extension for hardware-backed approvals.

    • Firmware 5.8 supports CTAP 2.3 and a preview of the WebAuthn signing extension.
    • Hardware-backed signing targets transaction approvals, AI agent authorizations, and payment confirmations.
    • Enterprise Attestation supports up to 16 relying-party identifiers.
  • Data Card

    Microsoft sets Entra passkey default and SMS retirement timeline

    2026-07-15CC-BY-4.0passkeys-webauthn

    Microsoft set a phased timeline to make passkeys the default Entra ID experience for users enabled for SMS or voice and to retire Microsoft-provided telecom authentication.

    • On September 1, 2026, in-scope users will be enabled and prompted to register passkeys.
    • Microsoft-provided SMS and voice delivery retires for public-cloud Entra ID on February 1, 2027.
    • Organizations with a continuing operational need can use a customer-managed telecom provider, while Microsoft recommends phishing-resistant methods as the primary path.

Frequently Asked Questions

What is a passkey?
A FIDO credential (public/private key pair) bound to a user and relying party. The private key stays on the device; the public key is registered with the service.
How is this phishing-resistant?
Credentials are origin-bound and never revealed; a signed challenge is produced locally after user verification (biometric or PIN).
CTAP vs WebAuthn?
WebAuthn is the browser API; CTAP connects clients to authenticators (platform or roaming security keys).
What’s the difference between multi-device and single-device passkeys?
Single-device credentials live only on one device; multi-device credentials can sync across an ecosystem under vendor security policies.
How do recoveries and device loss work?
RPs should provide recovery paths (additional authenticators, admin-recovery, or re-enrollment) while balancing phishing resistance and account takeover risks.