“Chaum’s approach to the protection of privacy can be thought of as having three layers. The first layer is public-key cryptography, which protects the privacy of individual messages. The second layer is anonymous messaging, which allows people to communicate via electronic mail (“email”) without revealing their true identities. And the third layer is electronic money, which allows people to not only communicate but to transact business via a computer network, with the same kind of privacy you get when you use cash. If you go into a store today and make a purchase with cash, no records are left tying you personally to the transaction. With no records, there is nothing to go into a computer database. The goal of electronic cash is to allow these same kinds of private transactions to take place electronically.”