A Research On Global Trust Model In P2P Environment

Security model of P2P networks is one of hottest research. Due to P2P network's distributed characteristics and lacking of centralized control, its security becomes an outstanding problem. Therefore it is necessary to establish a distributed trust mechanism to enhance the reliability of the P2P system. Trust model is the core of trust mechanism. By the collection, transmission and estimation of the historical action information of the peers in the network, the actions can be normalized and restricted by the peer trust value, the reliability of the P2P system is ensured to some extent.According to the research of current P2P network technologies and P2P trust models in China and abroad, an improved EigenRep global trust model is put forward. In the model, a concept named 'degree of trust link' is proposed and peer searching scope is controlled by the degree of trust link. As a result, the problems, such as the excessive cost of network performance, are solved. At the same time, an algorithm to update the values of the trust is also put forward. In the algorithm, the local values of trust of peers', which are involved in the selected trust link, will be updated according to the result of current service.Simulated experiments and result analysis show that the improved global trust model has high effectiveness in solving the problems, such as the excessive cost of network performance.An implementation scheme of building trust relationships among peers is provided by the improved trust model, and several useful attempts to solve secure problems existing in P2P networks are also made.