Initially, the Internet was designed to be used by government and academic users,
             but now it is rapidly becoming commercialized. It has on-line "shops", even
             electronic "shopping malls". Customers, browsing at their computers, can view
             products, read descriptions, and sometimes even try samples. What they lack is
             the means to buy from their keyboard, on impulse. They could pay by credit card,
             transmitting the necessary data by modem; but intercepting messages on the
             Internet is trivially easy for a smart hacker, so sending a credit-card number
             in an unscrambled message is inviting trouble. It would be relatively safe to
             send a credit card number encrypted with a hard-to-break code. That would
             require either a general adoption across the internet of standard encoding
             protocols, or the making of prior arrangements between buyers and sellers. Both
             consumers and merchants could see a windfall if these problems are solved. For
             merchants, a secure and easily divisible supply of electronic money will
             motivate more Internet surfers to become on-line shoppers. Electronic money
             will also make it easier for smaller businesses to achieve a level of automation
             already enjoyed by many large corporations whose Electronic Data Interchange
             heritage means streams of electronic bits now flow instead of cash in back-end
             financial processes. 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
             venerable answer to securing sensitive information, like credit-card numbers, is
             to encrypt the data before you send it out. MIT's Kerberos, which is...