Unfortunately, no amount of blockchains and zero-knowledge proofs can compensate for the fact that 15 year old has a 18 year old friend. Or the fact that other 15 year old looks older than some 20 year olds. Or the fact that other 15 year old's dad often leaves his wallet, with his driving license, unattended.

Over the next five years, you can look forward to a steady trickle of stories in the press about shocked parents finding that somehow their 15 year old passed a one-time over-18 age verification check.

The fact compliance is nigh-impossible to comply with is intentional - the law is designed that way, because the intent is to deliver a porn ban while sidestepping free speech objections.