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.
I think if you as a parent have router controls and block adult content on their mobile plan if they have one (which I have seen as an option), then you are already doing a lot.
Most routers from ISPs come with "adult" content filtering enabled by default I think, at least the ones I've had have had this on.
VPNs already work and I can't see them not working, so that's always an option I guess, but they are also still an option with ID laws (ie connect to a region where they have no such laws).
Children's safety online can't involve limiting access and tracking everyone who ever goes online with their national ID attatched to every request (basically).
I think it'd be better if we explored the option that involves a parent blocking websites either on your network or on a device they give to you.
Not that I'm doubting you, but is this a common thing? I've never even seen it as an option here in Canada, both on ISP supplied devices and on separate routers. Is it just because I'm using cheaper devices, or because on my region?