Abstract: In the P2P environment，parties communicate directly with exchange files or execute transaction in a peer-to-peer fashion.Peers have to manage the risks involved in the collaboration when the information about each other is incomplete.In traditional access control，authorization is assumed to be done before access is allowed.What’s more，the attributes can’t be updated when accessing.So it can’t be applied to the system of attributes dynamically changing very well.The factors that affect the reputation values are taken into account comprehensively.So a more accurate value is got.Then with the UCON model，UCON_P2P model is proposed.Because of the variability of attributes and the continuity of authority of the UCON，this model can be applied to P2P dynamic environment very well.

摘要： P2P网络是一种基于对等实体的数据交换方式，在数据交换协作过程由于用户的未知性、动态性，使得另一方会面临很大的风险。而传统的访问控制模型都是基于授权在资源使用之前，应用于相对静态的系统中，对于属性值动态更改的系统不能很好地适用。首先对P2P传统的信誉值计算方法进行了改进，对影响信誉值的多种因素进行了综合考虑，提出了一种比较准确全面的信誉值评估算法。然后从现今研究比较热的UCON模型出发，利用其属性的可变性以及授权的连续性等特点，提出了一种P2P的动态访问控制模型。