Data Security Using Certificateless Signature Cryptosystem

Abstract

This paper proposes a novel attack detection mechanism, using the trajectory of Arbitrator for identification while still preserving their location privacy communication. A location-hidden authorized message generation scheme is designed for two objectives: first, signaler signatures on messages are signer ambiguous so that the signaler location information is concealed from the resulted authorized message; second, two authorized messagess signed by the same signaler within the same given period of time ( temporarily linkable) are recognizable so that they can be used for identification. Optimistic fair exchange (OFE) protocols are useful tools for two participants to fairly exchange items with the aid of a third party who is only involved if needed. A widely accepted requirement is that the third party’s involvement in the exchange must be transparent message, to protect privacy and avoid bad publicity. At the same time, a dishonest third party would compromise the fairness of the exchange and the third party thus must be responsible for its behaviors. This is achieved in OFE protocols with another property called accountability. It is unfortunate that the accountability has never been formally studied in OFE since its introduction ten years ago. In this paper, these gaps are filled by giving the first complete definition of accountability in OFE where one of the exchanged items is a digital signature and a generic (also the first) design of OFE where transparency and accountability coexist