> I've also always been curious how a truely anonymous identity verification could possibly work.
You go to a store. You show the clerk your id and give him a quarter. The clerk pulls a scratch-off ticket from the front of a ticket tape. The ticket contains a token identifier.
It's anonymous. The clerk or his POS system knows your name and age, but doesn't know your number. The vendor providing the tape doesn't know your number or your name. The system accepting the token knows your number, but doesn't know your name. The token is only valid for a day after use, so loss and transfer isn't much of an issue.
It's the exact same process by which you buy lottery tickets in a world where they don't need to verify your identity when you redeem them. The lottery has no idea who bought a particular ticket, only that a ticket was bought. The clerk knows you bought a ticket, but doesn't know which ticket.
Obviously, Eavesdropping Eve looking over your shoulder knows both your name and your ticket number, but that's not a practical attack.
You go to a store. You show the clerk your id and give him a quarter. The clerk pulls a scratch-off ticket from the front of a ticket tape. The ticket contains a token identifier.
It's anonymous. The clerk or his POS system knows your name and age, but doesn't know your number. The vendor providing the tape doesn't know your number or your name. The system accepting the token knows your number, but doesn't know your name. The token is only valid for a day after use, so loss and transfer isn't much of an issue.
It's the exact same process by which you buy lottery tickets in a world where they don't need to verify your identity when you redeem them. The lottery has no idea who bought a particular ticket, only that a ticket was bought. The clerk knows you bought a ticket, but doesn't know which ticket.
Obviously, Eavesdropping Eve looking over your shoulder knows both your name and your ticket number, but that's not a practical attack.