That is exactly what EU is doing with its age verification law. Basically the service provider just has to accept the certificate and check that it is valid and all the cert says is "is over X years old".
And the fact that the companies have to implement the system themselves is just crazy. It is very obvious that if the government require such a check it has to provide the proof/way of checking just like in the physical world it provides the id card/passport/etc used for checking this.
> And the fact that the companies have to implement the system themselves is just crazy.
Isn’t this how most industry regulations work? It’s not like the government provides designs to car companies to reduce emissions or improve crash safety.
> just like in the physical world it provides the id card/passport/etc used for checking this.
In Sweden it wasn't the government that provided id cards, but the post office and banks. It became the government's job sometime after Sweden joined the EU, after the introduction of the common EUID standard.
And even then online identification is handled by a private company owned by banks: https://en.wikipedia.org/wiki/BankID_(Sweden)