The Studying Of Trust Relationship Modeling In Open Networks

By analyzing the characters of open networks and challenges to network security, summarizing the research fruits in trust problema, the thesis focuses on the subjective, dynamic trust relationship and the trust relationship modeling problem. The major contribution includes:Firstly, a trust evaluating model base on subjective logic is proposed In view of the affairs which happen on different time having different influence on trust value, a quantitative formula of trust relationship with attenuation element is given which describes the dynamic behavior of entities; According to that the direct experience is more believable than indirect experience, the thesis predigests the trust relationship graph to avoid computing recommendation trust repeatedly, and chooses a reasonable way to combine the recommendations from different recommendation paths to increase the veracity of combination, by comparing different computing ways. Meanwhile, a new combination rule is proposed which combines the different recommendations respectively.The simulations illustrate that the model is effective in entities behavior description and trust assessing, and prevents vicious cheat behavior with adaptability and good evaluating effect.Secondly, referring to social people trust relationship model, a trust information sharing scheme based on clusters is designed which divides the entities into different clusters according to their requirements. Based on the local information, entities can achieve distributed trust evaluating by changing information with the members in the same clusters effectively. Clusters are managed by administrators, the administrator of a cluster provides members in the cluster with services of identity authentication, information query, supervising the states of members and updating the list of members, and a scheme of by punishing asocial vicious recommending entities is designed to regulate the members in one cluster, and related protocols are also designed and described. Meanwhile an initializing trust value scheme based on assurance is designed in the thesis, by which the new entities can obtain appropriate chances to cooperate and share resources with others relying on their assurors.By a series of simulations, the validity and adaptability of the trust model and the scheme of initializing trust value are validated, the trust scheme increases the efficiency of trust query, and prevents the vicious recommendations, and reduces communications load, has a good evaluating effect.