> Is it technically possible to implement the way he suggests? Yes.

I actually don’t think it is. Fundamentally this kind of certificate is going to be revocable. It’s untenable politically to hand out irrevocable attestations that can be handed off to minors. If you allow that, the system has failed to prevent minors from accessing adult materials, and if you don’t then the system has failed to preserve privacy.

> To me the author seems either naive or straight up malicious.

I think just naive.