There is no need for a mechanism in this case; building such a thing would be a waste of time. Honestly, I was trying to respond to your question, and perhaps

There is no need for a mechanism in this case; building such a thing would be a waste of time. Honestly, I was trying to respond to your question, and perhaps I was too terse. But I don’t think the mechanism you ask for is possible (or desirable) today. In a future scenario with some type of universal identity there would probably be no need for such a mechanism.