A New Dynamic Trust Model For P2P Network

P2P service has become one of the most important applications in the Internet nowadays. However, due to its characteristics of decentralization, autonomy, dynamics, self-organization and heterogeneity, which have brought about great challenges to security issue. Currently, P2P Networks lack of effective mechanism which can guarantee the security. How to establish trust relationship among peers and then to manage the P2P networks effectually is an important problem. After in-depth research of security issue in P2P, this thesis presents a new dynamic trust model-DRTrust (Dynamic Recommend Trust) .DRTrust absorbs the advantages of the trust mechanism in the real-life world, evaluates peer's trust via quantitative method. It divides peer's trust degree into direct trust degree and commendatory trust degree. The direct trust is obtained through successful and unsuccessful bartering history records between peers. When calculate direct trust degree, a dynamic attenuation mechanism of trust value is introduced to enhance data's time-effect. The commendatory trust can be gotten from traded nodes through a recommendation protocol and can give more information about peers' behaviors in P2P network. The model negates the hypothesis in that the more trust value the more commendatory reliability, recommendation reputation is updated through the deviation of recommendation to increase its reliability. Finally, virtual reputation currency attribute is added to every node, it can enhance the peer's positivity of participation.DRTrust implements the trust model as a module of P2P system, and it doesn't affect the structure of the original P2P implementation. It consists of three parts: trust management, message route and database. The thesis describes the specific flow of work and design of sub-models. The simulation results show that DRTrust can resist more types of deliberate attack than other models, can improve the QoS in P2P network. At the same time, the model needs less overloads, which can apply more network circumstances.