A fairly basic version of anonymous verification would be that local stores sell an age token. You show them your ID, like you would for buying alcohol, and the

A fairly basic version of anonymous verification would be that local stores sell an age token. You show them your ID, like you would for buying alcohol, and they give you the token which could then be used with online services to prove you're over a certain age. It only becomes a problem if stores are forced to store the ID and link it to the token in some way.