A response I gave elsewhere in this thread. > > This authority will provide you with tokens indicating you are 18+ (or whatever age verfication you may need) These tokens are stored locally, and contain no identifying information other than a simple "is this guy 18+?" > So they're reusable? One token can be used for multiple age checks, right? > > If not, then think about what that means. > > 1. The token gets sent back to the authority for revocation. > 2. The token is authorised by the central authority as still valid. > 3. The token is uniquely identifiable > 4. The central authority knows who it issued each token for > 5. The central authority knows who has asked it the verify age. > > Sure, the company you're purchasing from may have no new information, but the central authority now has everything it needs to know: > > - How often you buy tobacco, alcohol or medications > - What discussion boards you are a member of > - Have you purchased anything age restricted from any store (e.g. propane from a DIY store)