There are actually ideas using crypto to provide proof of properties without a trusted entity having to know what the proof will be used for, and without the re

There are actually ideas using crypto to provide proof of properties without a trusted entity having to know what the proof will be used for, and without the requester of the proof being able to learn more about the identity. E.g. (in french) https://linc.cnil.fr/demonstrateur-du-mecanisme-de-verification-de-lage-respectueux-de-la-vie-privee https://linc.cnil.fr/demonstrateur-du-mecanisme-de-verificat... Now i think it is still either a dangerous slope, or it will end up inefficient, because of credential sharing; the typical modern idea to avoid that is to require the user to have a locked smartphone, wich is quite an intrusive requirement.