Fair Tracing Without Trustees for Multiple Banks.

In this paper we present a multiple bank electronic cash system based on group blind signature scheme, which offers a new kind of tracing mechanism. It provides conditional anonymity both for the customers and electronic coins under a judge. The coins can be marked using undeniable signature scheme so that the bank will recognize these coins at deposit. We also use the secret sharing scheme to trace the customer under the permission of a judge. The security of our scheme is analyzed. And compared with other works, our proposed tracing methods offer more privacy and do not need any trusted third parties. Our system is able to prevent from blackmailing, kidnapping, and bank robberies. Also we extend electronic cash system to multiple banks, it is more practical in the real life. [ABSTRACT FROM AUTHOR]