Re: [webauthn] devicePubKey → supplementalPubKeys (#1957)

> Couldn't this be solved by assertion-time attestation? "Hey I didn't get attestation during registration; please prove this key is hardware bound; my policy changed" sounds simpler from an implementation-POV

Assertion-time attestation is for the primary key, but the primary key might not _be_ hardware bound, nor have the other properties that sites are interested in.

Also, assertion-time attestation closes over the challenge, meaning that it has to be calculated for every assertion. The assertion for a supplemental key can be fixed and cached. (Doing an online assertion for every sign-in is a little fraught from both privacy and reliability perspectives. If a site wants a remote assertion for every sign in, they might want federation.)

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Received on Tuesday, 5 September 2023 16:52:33 UTC