We need to resolve four key technology issues before consumers and merchants anoint electric money with the same real and perceived values as our tangible bills and coins. These four key areas are security, authentication, anonymity, and divisibility. Commercial R&D departments and university labs are developing measures to address security for both Internet and private-network transactions. The answer to securing sensitive information, like credit-card numbers, is to encrypt the data before you send it out. MIT's Kerberos is one of the best-known-private-key encryption technologies. It creates an encrypted data packet, called a ticket, which securely identifies the user. To make a purchase, you generate the ticket during a series of coded messages you exchange with a Kerberos server, whom sits between your computer system and the one you are communicating with. These latter two systems share a secret key with the Kerberos server to protect information from prying eyes and to assure that your data has not been altered during the transmission. But this technology has a potentially weak link: Breach the server, and the watchdog rolls over and plays dead. An alternative to private-key cryptography is a public-key system that directly connects consumers and merchants. Businesses need two keys in public-key encryption: one to encrypt the other to decrypt the message. (Smith, 2000). Everyone who expects to receive a message publishes a key. To send digital cash to someone, you look up the public key and use the algorithm to encrypt the payment. The recipient then uses the private half of the key pair for decryption. Although encryption fortifies our electronic transaction against thieves, there is a cost: The processing overhead of encryption/decryption makes high-volume, low-volume payments prohibitively expensive. Processing time for a reasonably safe digital signature conspires against keeping costs per transaction low.