Study On Fair Exchange Protocols In Electronic Commerce

Electronic Commerce is the Internet-based exchange of tangible merchandize or in-tangible service between two or multi parts, so the fair exchange protocols have beenwidely used in electronic commerce.This dissertation investigate the fair exchange protocols and fair e-payment schemesfrom these protocols in electronic commerce, and focus attention on weakening the trustbases of the fair exchange protocols. We first discuss the fair exchange protocols with thethird party, but, in which a semi-trusted third party is introduced instead of the trustedthird party. Second, we simplify three parties to two parties farther, so the trust base isalso weakened in these fair exchange protocols. At last, we propose the ID-based signaturewithout trusted PKG, which makes it possible that fair exchange protocols between twoparties with no trust or weak trust base.The author obtains main results as follows:(1) Two new fair e-payment scheme are presented. In the first scheme, a semi-trustedthird party is introduced to provide a fair commerce environment. In the secondscheme, we improve the first scheme and, by converse using blind signature, presenta new fair e-payment scheme for electronic commerce, which simplified the commu-nication of the business process;(2) The basic model of Fair Exchange Signature Scheme is presented, which allows twoplayers to exchange digital signatures in a fair way and has various implementationson most of the existing signature schemes;(3) An Implementation of FESS from Schnorr signature is presented. Moreover, thesecurity proof is given under Random Oracle Model.(4) A low-computation model of simple partially blind signature is presented, fromwhich we raise two new simple partially blind signatures. The security proof is alsogiven under Random Oracle Model.(5) By converse using simple partially blind signature, we present a simple and effi-cient fair e-payment scheme. In the protocol, without any trusted third party, twoparticipants achieve the goals of fair payment with each other in a simple way ine-commerce business process. (6) We introduce the exact concept of ID-based signature without trusted Private KeyGenerater(PKG). Using Gap Diffie-Hellman (GDH) groups, we construct an newefficient ID-based signature scheme without trusted PKG. The scheme is proved tobe secure against existential forgery on adaptively chosen message and ID attack.(7) We discuss the security strategy of the RosettaNet and the security issues of theGrid. And then analyze and improve the security of RosettaNet, particularly in theGrid environment.