Research On Trust Model And Trust-based Application In Grid Environment

Grid is a brand-new network computing platform after the World Wide Web. It aims to provide an overall sharing of resources for users. However, because of its large-scale, distributed, heterogeneity and dynamic of grid resources, grid computing becomes quite complex and calls for higher and larger security needs than traditional network environment. Security is the key problem of grid computing, and trust problem is the core issue which we must face in the solution of security problem. So researches on trust and trust models seem quite necessary.Based on the study of existing trust models, this paper proposed a new trust model—a double-layers trust model with rewards and punishments mechanism to deal with trust relationships among entities in grid environment. The model joined identity authentication into trust initialization process. It considered direct trust and recommendation trust to assess overall trust value, so that it can assess more accurately the trust relationships among entities. In the searching of recommendation trust paths, the trust model screened the recommendation trust paths by improved ant colony algorithm (IACA) to prevent the joint fraud of domains. In the process of updating trust relationships, it used rewards and punishments mechanism to update trust relationships among entities and trust values of nodes, this is a good solution to security issues arising from nodes' malicious acts. In the processes of utilization recommended trust to establish trust relationships among domains, the paper proposed a feasible domain trust adjusting algorithm (DTAA) with contact experiences among entities from different domains, so that it is able to identify in advance malicious acts.Then, series of simulation experiments were carried on from validity, accuracy and security three aspects to assess the trust model, and verified effectiveness and convergence of improved ant colony algorithm. Experimental and analytical results show that the model can effectively solve security issues in grid environment. Finally, it applied the trust model to access control, put forward a trust-based access control decision-making framework in grid environment.