Electronic exchange check system on the Internet

This paper deals with a new payment scheme on the Internet, the electronic exchange check system, based on Nguyen´s (1997) scheme and Hwang´s (1997) scheme. The electronic exchange check system is a kind of electronic cash system which has pre-denoted receiver and effective time. The scheme satisfies all the basic requirements for an electronic payment scheme in the aspect of security and privacy. In particular, it provides the prior-restraint of double-spending as well as the detection of the identity of a double-spender after the fact