Research On D-S Theory-Based Trust Model In Grid

Grid security is the essential mechanism in grid computing systems. Grid system consists of various resources, and the resources have more features of change, geographical dispersion and heterogeneous systems, which make security issues of the grid system much more complex than the network. In order to solve the security issues incurred by the dynamic and uncertainty of grid environment, we introduce the trust mechanism into the access control, it is necessary to evaluate the network behavior of entities in grid computing. Thus, the evaluation of the entities' behavior can reflect his reliability.A new grid trust model, based on D-S theory and trust route, was proposed in this paper through to the exiting models research on trust definition, trust expression, trust memory and trust relations aspects and so on.The contributions of this dissertation are as follows:1. A new trust definition was made according to the characters of this model. Replaces the recommendation trust with the synthesis trust, trust expression more reasonable and computation simpler.2. Uses many kinds of trust expression: node direct trust, node synthesis trust, node historic trust, domain synthesis trust, domain historic trust. it causes a node in the grid to evaluate another more comprehensively and more freely.3. Proposed a trust memory management model based on trusts route with the merits of central and distributional. All trust information are saved in every trust route which distributes in each autonomous domain, using central method to inquiry trust information in the trust route, using similar method as internet router to update information for trust uniformity.4. Makes the computational formulas of node direct trust, node synthesis trust, node historic trust, domain synthesis trust and domain historic trust.5. Proposed an improved combination rule of D-S theory based on conflict ratio. by which can remove the influence of bad nodes very well, with faster centralism speed. 6. Using recently records to update node and domain trust values, to resolve the problem of trust weaken by time, it can not only avoid the difficulties of time factor choice and computation complex, but also prevent the infinite increase of transaction record sheet.