I prefer facial recognition. Probably good that there isn't a popular face-spoofer app, since it would put attention to the efficiency of these verifications.

I prefer facial recognition. Probably good that there isn't a popular face-spoofer app, since it would put attention to the efficiency of these verifications. Credit card info is a bad solution. In many countries they still are rare and it would very likely exclude as much adults as children. The real answer is that while we should expect children to be online, it is the responsibility of the parents to moderate their usage. Add a standard header to every http request to support filter solutions. That is the only viable solution that is of a technical nature. The whole ZKP idea is futile, no model works if you also have connection information, which states tend to save too. Anonymous internet usage is pretty awesome. For adults and kids for that matter. And that doesn't change because there are also bad advertisers that practically can identify and track you. If you want to protect kids, have those be imprisoned first. Strong opinion, I know, but also the correct one.