中文摘要：

P2 P系统中的节点具有随机性和动态性，如何建立节点间的信任关系，是亟需解决的难点和关键性问题。目前P2 P系统中主要采用传递模式算法计算节点的信誉值，分析了该算法存在的信誉值评估结果失真的问题，并对算法进行了优化。实验结果表明，信誉评估的优化算法得出的信誉值更加接近理想值，从而提高了P2 P系统对恶意节点的识别能力。

英文摘要：

In P2P（Peer-to-Peer）system,peers present the characteristics of random and dynamic,and then how to es-tablish a trust relationship between peers is a difficult and key problem that is urgent to solve.At present,the algorithm of reputation computing based on transitive mode is used in P2P system.In this paper,this algorithm was optimized based on analyzing its distortion problem of reputation assessing value.The simulation results show that the reputation assessing value of the optimized algorithm is closer to the ideal value.In this way,the discovery ability of malicious peers is enhanced at the same time.