P2P网络中基于信任的风险评估研究-智能与分布计算实验室

P2P网络中基于信任的风险评估研究

姓名	章华娟
论文答辩日期	2007.06.06
论文提交日期	2007.06.08
论文级别	硕士
中文题名	P2P网络中基于信任的风险评估研究
英文题名	Trust-Based Risk Assessment in Peer-to-Peer Network
导师1	李瑞轩
导师2
中文关键词	对等网;风险;信任;风险评估;风险控制
英文关键词	peer-to-peer;risk;trust;risk assessment;risk control
中文文摘	随着网络的飞速发展，基于P2P（peer-to-peer）结构的分布式应用越来越多。P2P网络具有负载均衡，信息资源丰富等优点。但是，由于P2P网络的匿名性、分散性和动态性等特点，使得网络中节点行为缺乏管理和约束，使得P2P网络的具有突出的安全问题。针对以上问题，提出运用基于信任的风险评估方法以提高对等点的安全防御水平。基于信任的风险计算方法的目的是将P2P网络中对等点间信息交互存在的安全威胁量化为风险度。信任计算是研究基于信任的风险计算的基础。提出了一种基于评价的信任计算，根据节点的交互历史评价和节点的信任值计算节点的全局信任值，同时考虑了历史评价数据的时间衰减效应。基于信任的风险计算方法是在传统风险函数基础上，综合考虑了通过研究信任和风险的函数关系所得到的信任风险，是信任机制与传统风险函数相结合的结果。并对信任计算和风险计算进行的仿真实验，验证了计算方法的可行性和有效性。基于信任的风险评估模型给出了对对等点信息交互中存在的风险进行风险评估的具体方法和流程。计算风险的大小是风险评估工作的第一步，接着实现风险度到风险等级的映射。为适应P2P网络无中心节点管理的特点，对风险语句和风险评估报告的结构进行规范化。模型还具体给出了对风险事件进行排序的算法和风险控制的方法策略。最后运用一个实例展现了模型的具体操作过程。在P2P文件共享系统中简单实现了基于信任的风险评估模型，给出了模型的整体框图以及主要模块的具体设计和实现流程，并分析了系统的性能。
英文文摘	With the rapid development of network, there are more and more distributed applications based on peer-to-peer structure. Peer-to-peer network takes advantages of effective payload balancing and immense information and resources. But p2p network which is lack of central controlling and constraints on behaviors of peers in the network gets several obvious security problems. To solve these problems, this paper proposes a trust-based risk assessment method in P2P networks. The purpose of trust-based risk assessment method is to quantitate the threatening factors in interactions of peers in P2P network as risk value. Trusted risk is the base of research on trust-based risk calculation. This paper proposes trust-based risk calculation, according to historical records of interactions and trust value. Risk calculation based on trust integrates trust and risk into trusted risk based on traditional risk functions, combining trust mechanism and traditional risk functions. The simulations on trust and risk calculation proved feasibility and the effectivity of calculations. Trust-based risk assessment model proposes a flow of risk assessment upon risks of peers' information interaction in P2P network. The first step is to get the quantity of risk，and then implement the mapping from risk values to risk levels . To solve non-central controlling of P2P network, risk sentences and risk assessment reports' structure and formation is standardized. The model proposes strategy of sorting and controlling of risks. The trust-based risk assessment model is carry out in P2P file sharing system. Introduces components of the model , main designing and work flow. Moreover , analyzing performance of the system.