Research On Fair Exchange Of Digital Signatures

With the rise and development of the internet technology in recent years, more and more people carry on commercial affairs and the service activities through internet. All the exchanged information through the internet needs to be authorized in the form of electronic data. However, Because of the openness of the internet, the way that can touch more users also bring a tremendous possibility to cheat. How to ensure the various valuable electronic data to exchange fairly and safely have become an important topic in the network information security field. In this paper, we aim at such an application demand, research on the fair exchange of the digital signatures. The main contributions are as follows.1. The ways and technologies to achieve fair exchange of digital signatures are analyzed, and classified them in accordance with the different mechanism.2. Gradual exchange protocol that not need trusted third party is discussed. Its development status is described and two typical gradual exchange protocols are analyzed; the third party protocol that need trusted third party is discussed. Specially, the development status of the third party protocol is described, and classified them according to the different intervened level and intervened way of the third party; some typical third party protocols are analyzed.3. Some typical concurrent signature schemes are discussed. The advantages and flaws of some exiting schemes are analyzed.4. Based on the idea of the offline third party and non-interactive verification technology, a new abuse-free contract signing protocol based on the RSA signature is proposed. New protocol possesses the following properties: off-line TTP, fairness, timely termination, abuse-freeness and TTP's statelessness. Its security and efficiency are also analyzed.5. A new efficient ID-based Concurrent Signature scheme is proposed. New scheme not only make up the insufficiency of some exiting schemes, but also can better embody the fairness of concurrent signature. Analysis shows that the new scheme's efficiency is better than that of some existing schemes. It is proven to be existential unforgeable against chosen message attack under the random oracle model.