针对目前大规模 P2P 系统不能有效处理恶意节点攻击的问题，该文提出一种新的基于信誉与风险评价的

P2P 系统信任模型，该模型考虑到节点的动态行为影响信任度计算的不确定性，引入风险因素，并提出采用信息

熵理论来量化风险，将实体之间的信任程度和信任的不确定性统一起来。仿真试验及分析表明，该信任模型能够有

效识别恶意节点，相比已有的一些信任模型较大程度地提高了系统成功交易率，可以使节点之间更有效地建立信任

关系。

-View of the current large-scale P2P systems can not effectively deal with malicious nodes to attack the problem, the paper presents a new risk assessment based on credibility and trust model of P2P system, the model taking into account the impact of the dynamic behavior of nodes trust the calculation of uncertainty, the introduction of risk factors, and to make use of information entropy theory to quantify the risks, will be the degree of trust between the entities and trust uncertainty unified. Simulation and analysis show that the trust model can effectively identify the malicious node, compared to some of the existing trust model to a greater extent to improve the system the rate of successful transactions, you can make between nodes more effectively to establish a relationship of trust.