Comment by orwin

If it's not a zero knowledge system, it's a bad system. I know i will trigger the ancaps here, but this is typically a case where the government has to be on it, and _has_ to be great.

Like a secret, digital ID that will allow you to generate a code easily (with both an app for the ease of access, and a website where you just have to input your ID and a validation code that change every X years and that you receive with your voter ID or something).

This code is an auth token to an API that will just respond "OK" if the token is a valid token, but should have no idea who issued it.

The advantage is that if you extends it to be send before an online purchase, or to be send SM to limit some features before like, 16 yo, you can make it so that even if the government lies and tries to identify who generated the auth token, if multiple private companies use a third party SaaS to handle it, the government can't know why the token was used.