alt Hacker NewsIt’s not my invention. It’s in the article. The physical card proposed contains nothing traceable. “They issue a card that says only one thing: "over 18". The card carries official seals, signatures, and anti-forgery features.”
If you put an id on the card, then it’s a layer of indirection, but you’ve still handed them a unique personal identifier.
Traceable credentials are fundamentally not privacy preserving, because that’s what traceable means.
You're now arguing about something which isn't even in the proposal from the EU, it's a hypothetical from the article which attempts to draw a parallel with existing physical id (I guess to demonstrate to people that this already happens regularly with passports, ID cards, driving licenses etc).
That existing physical ID is government issued, has an issue no, usually has a photo on it, often other biometrics nowadays, and is definitely traceable!
Absolutely such a proposal cannot be fully privacy preserving, because at the very least it gives away your age, but also probably other identifiers.Just like your browser that you're using right now gives away a lot of information which advertisers use to fingerprint you like fonts etc. This sort of solution requires a central issuer/authority to know about the tokens, there's no way round that as there is no way round governments issuing passports if you want border control.
The goal is that it'll preserve much better privacy than uploading passports etc to random websites, which I think it will.