The Research Of Trust Model Problem In P2P Network

With the rapid development and popularization of internet, Peer-to-Peer (P2P) network technology has a great development. Different from the traditional network of"content-content"C/S model, P2P networks are using distributed architecture; each mode is both a client and server. This kind of a structure makes P2P technology widely used in file-sharing, distributed computing, collaborative systems, in-depth search engine, e-commerce and other fields. Recently the P2P network is in a stage of developing and there is no mature standard. In the other side, with the characteristics of own-distributed, P2P networks lack of centralized control, which makes the security of P2P network become an outstanding problem. In particular, although P2P file-sharing system provides the share of resources with convenience, it can not guarantee the authenticity of resources. In addition, open and anonymous P2P system allows any node to join and leave. During these nodes, there are a number of malicious nodes which may cause damage to the system and exacerbate the insecurity of the P2P system. As the traditional centralized mechanism of trust is no longer fit the requirements of P2P system, it is necessary to establish a trust mechanism to improve system security.In this dissertation, the author provided an overview of P2P network topology and the application of P2P technology, compared the P2P model and C / S model and also discussed P2P networks and the current security problems, analysized the malicious behavior. Second the author analysized confidence-building mechanisms and resources of algorithms under the P2P environment. By combining the credibility of the introduction of node, the author offered an improved search resources algorithm.This algorithm has reduced the possibility of link of the client nodes and malicious nodes which had been set up and increased the services of the reliability of node by setting the node to determine the credibility of the parameter values. The algorithm also set up an effective response to information received by the node number of the maximum section, to prevent one node after setting up links to information requests issued can't satisfy the requirements of the client node. Client nodes can be discarded this link and create a new link with other nodes, in order to increase system reliability, the success of the search rate of the node.At the same time, the author proposed a kind of trust model based on improving resources-searching algorithm, which gives a new credibility to updated algorithm. This model is for the anonymity of P2P networks, the using-service time. It will do a credible calculation to the logarithm of the evaluation of the estimation. At the same time, it can efficiently prevent the malicious node's attraction to the normal nodes and credible nodes. In other side, this model can also prevent the malicious from improving the credibility of each node by small group cooperation.Finally ,the author gave a brief introduction of simulation platform of JADE 2.5,and the trust model has been simulated through the JADE2.5.The results show that this model is better than the existed model in service quality, reducing the possibility of being attacked by malicious node, improving security of system as well as the success rate of service. However, there are still come deficiencies which need to be further improved in the future.