How is electronic money (e-money) possible?
Public-key cryptography and digital signatures (both blind and non-blind signatures) make e-money possible. It would take too long to go into detail how public-key cryptography and digital signatures work. But the basic gist is that banks and customers would have public-key encryption keys. Public-key encryption keys come in pairs. A private key known only to the owner, and a public key, made available to everyone. Whatever the private key encrypts, the public key can decrypt, and vice verse. Banks and customers use their keys to encrypt (for security) and sign (for identification) blocks of digital data that represent money orders. A bank “signs” money orders using its private key and customers and merchants verify the signed money orders using the bank’s widely published public key. Customers sign deposits and withdraws using their private key and the bank uses the customer’s public key to verify the signed withdraws and deposits.
