Many might’ve seen the Australian ban of social media for <16 y.o with no idea of how to implement it. There have been mentions of “double blind age verification”, but I can’t find any information on it.
Out of curiosity, how would you implement this with privacy in mind if you really had to?
You would prove something like “I possess a private key that matches a public key that is in this list of public keys belonging to people at least X years old”. But without revealing which item in the list is the specific one for you. Which is the zero knowledge proofs’ cool trick.