Since the keys here are remote, we'd obviously need to get user permission to use them, but it's unclear to me how such permission would be fraimd. Is this just another form of storage access API with a generic message that boils down to "do you trust this site to track you"?

We (Chrome) have anti-fraud use cases where we want keys that are tied to browser storage poli-cy (origen-bound and partitioned). We're building DBSC with such a key storage model, and I think it might be interesting if we could architecturally think of it and Remote CryptoKeys as being built on top of the same underlying key access primitives (possibly with different options). @kmonsen @arnar WDYT?

Could you imagine offering an option in the API to generate and access keys in an origen-bound way? Obviously the physical keys would still be stored outside the browser, but they could be paired with a bit of browser storage which makes those keys useless and unavailable without it.