With many jurisdictions introducing age verification laws for various things on the internet, a lot of questions have come up about implementation and privacy. I haven't seen anyone come up with a real working example of how to implement it technically/cryptographically that don't have any major flaws.
Setting aside the ethics of age verification and whether or not it's a good idea - is it technically possible to accurately verify someone's age while respecting their privacy and if so how?
For an implementation to work, it should:
- Let the service know that the user is an adult by providing a verifiable proof of adulthood (eg. A proof that's signed by a trusted authority/government)
- Not let the service know any other information about the user besides what they already learn through http or TCP/IP
- Not let a government or age verification authority know whenever a user is accessing 18+ content
- Make it difficult or impossible for a child to fake a proof of adulthood, eg. By downloading an already verified anonymous signing key shared by an adult, etc.
- Be simple enough to implement that non-technical people can do it without difficulty and without purchasing bespoke hardware
- Ideally not requiring any long term storage of personal information by a government or verification authority that could be compromised in a data breach
I think the first two points are fairly simple (lots of possible implementations with zero-knowledge proofs and anonymous signing keys, credentials with partial disclosure, authenticating with a trusted age verification system, etc. etc.)
The rest of the points are the difficult ones. Some children will circumvent any system (eg. By getting an adult to log in for them) but a working system should deter most children and require more than a quick download or a web search for instructions on how to circumvent.
The last point might already be a lost cause depending on your government, so unfortunately it's probably not as important.
My point is that we can't rely on parental oversight only because some plain won't... and in your case, even actively trying may fail (it's not your fault). And there's always going to be loopholes in every system. Clever kids will get by most verifications, and if they don't, that's likely to mean the verification gets too invasive to be worth it. The best, though not perfect system is to have parental oversight + impartial verification + platform responsibility. This will reduce but not eradicate the problem.
Problem is an OS is not a useful part of this. My kids are perfectly able to install linux on a pi - and this is something I want to encourage in general (I don't think they have, but they could), thus giving them root access - including access to things in the package repo that I may not approve of. It is a hard problem and I can't always be there.