P2P文件共享网络的信任评价机制正面临着各种恶意攻击,例如聚集反馈、合谋欺骗和虚假交易,严重影响了整个系统的性能.为了保护P2P文件共享网络,提出了一种高精度自适应声誉机制,简称AARep机制(accurate and adaptive reputation mechanism).经过分析发现,在信任评价系统中,除了对交易的评价,相关的交易信息也起着重要的作用.其贡献在于:1)通过以下手段,增加了信任值计算的精度:引入交易衰减函数,根据交易次序区分交易的重要程度；过滤掉具有低相似度的可疑节点；利用置信因子来反映观测值的可靠性；2)为了使置信因子起效,提出了一种简单的交易验证协议.实验结果表明,AARep能够显著消除或者减少各种攻击的威胁,提高系统性能.%Current reputation schemes, employed by an existing P2P file sharing network are faced with many threats, such as aggregate feedback, conspiracy, and fake transactions, which have affected the performance of whole system. To protect the P2P file sharing network, this paper proposes an accurate and adaptive reputation mechanism (AARep). In the paper, after an elegant analysis, it is concluded that besides the transaction evaluation, the relative and underlying transaction information plays an important role in the reputation system. This paper makes two important contributions. First, trust value computation is enhanced by adopting a decay function to display the importance of every transaction in sequence order. This weeds out suspected nodes that are less similar and utilizes the confident factors of reflect reliability in all observed values. Second, to make the confidence factors work, a simple transaction validation protocol is developed. Experimental results show that AARep can significantly eliminate or minimize the effects of a verity of attacks and improve the overall performance effectively.
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