Some Approaches to Electronic Cash

Vlad Kolesnikov
Department of Computer Science
University of Toronto


It has become clear that the Internet provides an extremely efficient means to market and sell any services and merchandise. The existing payment and authentication schemes (credit cards), while still functional, are rapidly becoming obsolete and unacceptable because of poor security guarantees and compromise of personal data of the consumers. With the continued use of current identification and payment techniques, combined with further development of technology and merging of government and private databases, amazingly complete dossiers can be easily compiled and accessed on every individual. The use of digital certificates and other secure means of authentication only makes this problem worse, as those dossiers become undeniable.

Intuitively, electronic cash is a convenient replacement to current electronic payment schemes, designed to provide anonymity (untraceability of payments) for users and security for all participants of the scheme. It should be efficient (in terms of amount of computation and communication), and have the off-line property (bank need not be contacted in real-time to authorise transactions). Other features, such as coin divisibility and transferability are also desirable.

In this presentation we discuss several of the most famous techniques in the area of anonymous electronic cash (based on research of David Chaum and Stefan Brands), and briefly mention their applicability to other areas, such as authentication.

Colloquia Series page.