Research And Application Of Verifiably Encrypted Signature Based On Bilinear Maps

With the rapid development of computer and electronic communication technology, information security becomes one of the most important problems which need be solved at once in information society. Cryptography is the core technology in solving problems of information security. As key technology in cryptography, digital signature plays important roles in information certification. Verifiably encrypted signature, which is a special digital signature scheme, can realize signature and encrypt which can not be completed by common signature scheme. At the same time, efficiency of fair exchange protocol depends on efficiently verifiably encrypted signature scheme, which is the significant foundation of fair exchange protocol. So, studying verifiably encrypted signature scheme has important application value. It also becomes research focus in this paper. Against lower efficiency, insufficient security prove problem and lower trustful of private key generator problem, a provable secured bilinear-based verifiably encrypted signature scheme and a half-trust private key generator-based verifiably encrypted signature scheme are proposed. Moreover, the paper applies the provable secured bilinear-based verifiably encrypted signature scheme into fair exchange protocol.Firstly, the paper designs a provable secured bilinear-based verifiably encrypted signature scheme. In the scheme, adjudicator signs a guarantee to ensure his valid behaviors when resolving conflicts, so that action of adjudicator is guaranteed. Security depends on hard problem of bilinear maps. Formal prove method is used to demonstrate that scheme is conform to security requirements.Secondly, an efficient half-trust private key generator-based verifiably encrypted signature scheme is designed. Combing signature technology and bilinear maps technology, the problem of completely trusting of private key generator is solved. Not only the fault, user denies signatures, is preventing and the disfigurement, private key generator forges signature,is eliminated. The hard problem of bilinear maps ensures the security of scheme.Finally, by applying the design idea and method of provable secured bilinear-based verifiably encrypted signature scheme, a fair exchange protocol is proposed. After giving protocol modules and normative modules, the paper designs the fair exchange protocol in detail. At last, fairness, security and so on are analyzed.