> Just presented at ICETE2005 by Daniel Nagy: > > http://www.epointsystem.org/~nagydani/ICETE2005.pdf > > Abstract. In present paper a novel approach to on-line payment is > presented that tackles some issues of digital cash that have, in the > author s opinion, contributed to the fact that despite the availability > of the technology for more than a decade, it has not achieved even a > fraction of the anticipated popularity. The basic assumptions and > requirements for such a system are revisited, clear (economic) > objectives are formulated and cryptographic techniques to achieve them > are proposed.
This is a thorough and careful paper but the system has no blinding and so payments are traceable and linkable. The standard technique of inserting dummy transfers is proposed, but it is not clear that this adds real privacy. Worse, it appears that the database showing which coins were exchanged for which is supposed to be public, making this linkage information available to everyone, not just banking insiders. Some aspects are similar to Dan Simon's proposed ecash system from Crypto 96, in particular using knowledge of a secret such as a hash pre-image to represent possession of the cash. Simon's system is covered by patent number 5768385 and the ePoint system may need to step carefully around that patent. See http://email@example.com/msg04483.html for further critique of Simon's approach. CP