Wallet Databases with Observers

Previously there have been essentially on!? t\vo models for computers t h a t people can use to handle ordinary consumer transactions: <i:i :he tamper-proof module, such as a smart card, that the person cannot modify or probe; and ( 2 ) the personal workstation whose inner working is totally under control of the individual. The first par t of this article argues that a particular combination of these two kinds of mechanism can overcome the limitations of each alone. providing both security and correctness for organizations as Ivell as privacy and even anonymity for individuals. Then it is shown horn this conihined device. called a wailet. r a n carry a. dat.a.base containing personal information. The construction presenred ensures that no single part of the device (i.e. neither the yamper-proof part nor the xvorkstat.ion) can learn the contents of t h e database thls information can only he recovered by the tLvo parts together.