The ESPRIT Project CAFE - High Security Digital Payment Systems

. CAFE ("Conditional Access for Europe") is an ongoing project in the European Community's ESPRIT program. The goal of CAFE is to develop innovative systems for conditional access, and in particular, digital payment systems. An important aspect of CAFE is high security of all parties concerned, with the least possible requirements that they are forced to trust other parties (so-called multi-party security). This should give legal certainty to everybody at all times. Moreover, both the electronic money issuer and the individual users are less dependent on the tamper-resistance of devices than in usual digital payment systems. Since CAFE aims at the market of small everyday payments that is currently dominated by cash, payments are offline, and privacy is an important issue. The basic devices used in CAFE are so-called electronic wallets, whose outlook is quite similar to pocket calculators or PDAs (Personal Digital Assistant). Particular advantages of the electronic wallets are that PIN..