P2P网络论文P2P信任模型与搜索技术研究.doc

P2P网络论文：P2P信任模型与搜索技术研究 【中文摘要】P2P (Peer-to-Peer)网络是目前的研究热点,在现实中取得了广泛的应用。P2P不同于传统的基于C/S(客户机/服务器)模式的网络,强调加入节点的逻辑对等关系,网络中的每个节点既可以作为客户端获取服务也可以作为服务器向其他节点提供服务,两个对等点可以直接互连进行文件传输,整个传输过程无需中心服务器的介入。由于P2P网络具有匿名性和高度自主性的本质属性,节点可以随意的加入、离开网络,部分节点在缺乏有效管理的情况下上传虚假资源、病毒干扰系统的正常运行,降低P2P网络的性能。对P2P的安全性提出了挑战,信任模型的引入可以很好的规范节点的行为,减少恶意节点的数量,提高P2P网络的可用性。另外,如何从众多资源中快速、准确的搜索到自己感兴趣的,安全可用的资源,是P2P搜索研究的一个重点。信任模型在P2P安全方面起着重要的作用,通过分析已有信任模型的优缺点,提出一种基于超级节点的P2P信任模型TSN (Trust Super Node)。考虑节点的响应时延因素,改进了模型节点加入算法和节点信任值的计算方法。TSN模型中对节点的信任值采用了直接信任和问接信任相结合的方式,提高了信任值计算的精确性,模型还采取了相应的健壮性策略,增强了抗攻击能力。通过仿真结果表明,与已有的信任模型相比,TSN具有较高的成功请求率和系统安全性。分析了现有搜索算法的优缺点,结合TSN信任模型,改进源节点请求算法和中继节点的转发、响应算法,提出了基于信任模型的搜索算法SAT (Search Algorithm based on Trust Model),使查询请求能命中信任值高的节点,而信任值高的节点能提供真实可靠的资源,从而提高搜索的成功率。同时,采取了高速共享资源缓存机制和无重复转发机制以减缓搜索的时延。仿真实验表明,与Random-walk算法相比,SAT算法具有更高的搜索成功率和更短的搜索时延。 【英文摘要】P2P (Peer-to-Peer) network is a new kind of network that had obtained wildly application. P2P changes the mode of tradition network named C/S (Client/Server), demands logical reciprocal between peers, every peer in network can play two role both as client that acquires services and as server that provides services, files can transport directly between two peers without the help of center server.Peers can add in and off network as one pleases own to that P2P network’s essential attribute named anonymity and independent, some peers upload fake resource, computer virus deliberately under the situation without management in order to disturb system operation. The measure that pull trust model in P2P network can reduce the number of malicious peers and make peers’behavior standard, improve the availability of P2P network. How to search the needing resource fast and accurate from share files is a research focus for P2P technology.Author analysis features and defect about these model existed, propose a trust model based on super node named TSN(Trust Super Node). This model improves these algor