Re: [webauthn] How is an RP to know if a packed attestation root certificate is used for multiple authenticator models? (#1998)

I've interpreted this requirement to be a (mostly unenforceable, as you point out) requirement on authenticator vendors. I agree that it's not enforceable by anything other than a certification procedure, with the authenticator vendor honestly documenting its production processes to the certification body.

I think it's worthwhile to have this as a normative expectation stated in the spec, but I agree it's a bit misleading that the `packed` verification procedure includes the step "Verify that _attestnCert_ meets the requirements in [ยง 8.2.1 Packed Attestation Statement Certificate Requirements](https://www.w3.org/TR/webauthn-3/#sctn-packed-attestation-cert-requirements)", and this being one of the requirements in that section.

Although on the other hand, the next step of the verification procedure is:

>- If _attestnCert_ contains an extension with OID 1.3.6.1.4.1.45724.1.1.4 (id-fido-gen-ce-aaguid) verify that the value of this extension matches the [aaguid](https://www.w3.org/TR/webauthn-3/#authdata-attestedcredentialdata-aaguid) in _authenticatorData_.

So I guess one could also argue that that implies the RP doesn't need to verify the "If the related attestation root certificate is used for multiple authenticator models" part?

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Received on Thursday, 16 November 2023 10:39:20 UTC