FCP FIDO Authentication Methods 2

Question 1

Which cryptographic operation does a FIDO2 authenticator perform during the authentication ceremony?

Accepted Answer

It signs the authenticatorData and clientDataHash with the credential's private key

Answer

During FIDO2 authentication, the authenticator signs the concatenation of authenticatorData and clientDataHash using the credential's private key, producing an assertion signature.

Question 2

What is the purpose of the 'up' (user presence) flag in the authenticatorData structure?

Accepted Answer

It signals that a test of user presence was performed, such as a button press

Answer

The 'up' flag in authenticatorData indicates that the authenticator performed a test of user presence, typically a physical touch or button press.

Question 3

A roaming authenticator connected via NFC is used to authenticate to a website. Which transport is being used?

Accepted Answer

NFC

Answer

NFC (Near Field Communication) is one of the defined CTAP transports for roaming authenticators communicating with a client platform.

Question 4

What differentiates a 'second-factor' (U2F-style) flow from a 'first-factor' passwordless flow in FIDO?

Accepted Answer

Passwordless requires user verification (UV) at the authenticator; second-factor requires only user presence

Answer

In a passwordless first-factor flow the authenticator must perform user verification (PIN, biometric) to replace the password, whereas U2F-style second-factor flows require only user presence.

Question 5

Which field in a WebAuthn PublicKeyCredentialRequestOptions limits which credentials are acceptable during authentication?

Accepted Answer

allowCredentials

Answer

The 'allowCredentials' field contains a list of credential descriptors that the relying party will accept during an authentication ceremony.

(FCP) FIDO Certified Professional Practice Test

(FCP) FIDO Certified Professional Practice Test

FCP FIDO Authentication Methods 2