One of the problems facing the builders of thèInformation Superhighway' is how to charge for services. The high costs of billing systems suggest that prepayment mechanisms could play a large part in the solution. Yet how does one go about making an electronic prepayment system or indeed any kind of payment system robust? We describe some recent systems… (More)
We describe the successful introduction of cryp-tology into a new application area-protecting pre-payment electricity meters from token fraud. These meters are used by a number of utilities from Scotland to South Africa, and they present some interesting security challenges.