If you read the guidelines they actually want to implement a double-blind approach with ZKPs, which imo is significantly better than a challenge-response pub key system in term of privacy.
If you're not familiar this would mean the verifier doesn't learns anything except a statement about attributes (age, license, etc); and the EU doesn't learn what attributes have been tried to verify or by who.
What would need to happen in the United States to implement a reliable ZKP age verification system - and how long would it take to roll it out?
Asking because it feels like the Titanic has sunk, and we're eschewing a floating door because the coast guard has regulation conformant life rafts that would work better.
> United States to implement a reliable ZKP age verification system
(my emphesis)
Realistically at least 3-4 years, assuming they want to keep the same goals as eIDAS. I think the (software) implementation will be the least costly part, time-wise; but it takes a long time before everyone adopts a new social system. Especially in the US where there has been no precedent for digital identification. Even with full control of your own ID & and solid implementation details, there will be push-back just for suggesting that people/companies should adopt it.
If you're not familiar this would mean the verifier doesn't learns anything except a statement about attributes (age, license, etc); and the EU doesn't learn what attributes have been tried to verify or by who.