[IEEE SMC'03 2003 IEEE International Conference on Systems, Man and Cybernetics. Conference Theme - System Security and Assurance (Cat. No.03CH37483) - Washington, DC, USA (Oct. 5-8, 2003)] SMC'03 Conference Proceedings. 2003 IEEE International Conference on Systems, Man and Cybernetics. Conference Theme - System Security and Assurance (Cat. No.03CH37483) - Designated-receiver proxy signature scheme for electronic commerce