Re: [webauthn] First factor authenticator selection

@Kieun U2F authenticators can never be first factor as they do not allow storage of a User ID. What is more, whether or not the actual key is a resident key is not relevant in a U2F context: the key handle supplied by the RP is the only link between the user account and the signature.  Even if an authenticator would support returning an assertion based on AppID (U2F speak for the RPID), the returned signature does not contain any indication of which credential was used to generate it. They only way to identify the account for such a signature would be to validate the signature against all public keys stored by the RP...

I believe U2F authenticators should never be returned when `requireResidentKey` is set.


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Received on Monday, 16 October 2017 11:31:33 UTC