【作者】 徐磊；

【导师】 张宏莉；

【作者基本信息】 哈尔滨工业大学 ， 计算机科学与技术， 2011， 硕士

【摘要】 BitTorrent(简称BT)是当今互联网上最为流行的P2P文件共享系统之一,其匿名性、开放性以及高效性赢得了越来越多用户的青睐,BT客户端也得到了日益广泛的应用,仅在2004年,BT流量就已经占据了整个P2P流量的53%,近年来研究表明,P2P流量已经占据了整个Internet流量的70%。然而正是这些特性和大规模的流行使BT系统面临着严峻的安全风险,出现了一系列安全问题,其中文件污染问题因其难以防御和严重的危害性越来越受到重视,成为亟待解决的重要问题之一。BT文件污染主要分为种子文件污染、索引污染和数据污染。其中种子文件污染比较简单,本文不做研究。索引污染和数据污染可以相互影响,形成更复杂的复合型污染方式,他们通过提高虚假节点和文件内容被其他节点请求的几率来达到占用其连接数和下载带宽,降低其下载速度的目的,从而使网络中的资源可用性大大降低。由于索引污染技术和数据污染技术的复杂性和多样化,同时也缺乏系统的研究方法及理论,所以本文着重对索引污染和数据污染进行深入的建模研究分析,为BT网络文件污染评价方法和指标体系提供科学的参考依据。本文首先介绍了BitTorrent的相关背景知识,并对现有的文件污染技术进行了深入的剖析,概括总结了几种常见的污染模型和污染对抗模型;其次,通过分析这些模型的优缺点以及适用范围,指出了现阶段有效的污染模型需要考虑的因素;然后提出了一个索引污染和数据污染相结合的混合污染模型,该模型结合了黑名单机制、节点优先选择策略等影响污染效果的关键因素,并引入了块内并行度的概念,对污染效果和污染代价进行了建模。最后,设计和实现了高性能分布式污染平台,通过对BT系统进行测量和对实验结果的观察、分析,验证了混合污染模型能够在污染建模方面反映BT系统索引污染和数据污染的攻击效果,是真实情况的一种模型抽象,并通过该模型计算出污染效果和污染代价这两个指标值,为BT网络文件污染攻击的评价提供了依据。更多还原

【Abstract】 BT (BitTorrent) is currently one of the most popular P2P file sharing systems. More and more users like the anonymity, openness and efficiency of BT, and many BT clients are widely used nowadays. In 2004, BT has occupied 53% of the entire P2P traffic, and in recent years, P2P traffic is 70% of the entire Internet traffic. So the BT security is becoming more and more important due to the prevalence, there are indeed many problems in BT network, file pollution is one needed more attention because of the urgency and harm, which is also one of the issues being debated.BT file pollution is including torrent pollution, index pollution and data pollution. Torrent pollution is simple, and we do not work on it. Index pollution and data pollution can both exist alone or combined with each other to form a more complex and subtle mode of pollution. The goal is to increase the probability of bad peer choice, to consume the bandwidth and connections of other nodes, and finally to reduce the download speed and let the network resource become unavailable. The index pollution and data pollution technology are relatively complex, and are also lack of systematic research methods and theories, we focus on the index of pollution and data pollution to analysis model for the BT network file pollution, to provide a scientific reference of BT network.In this paper, we introduce the BitTorrent protocol, the background knowledge and analysis the files polluting technologies. And then introduce several common models and pollution resistance models, analyze the focus of these models, the advantages and how to use, and the pointed out that this effective pollution model must take into consideration. Then we propose a combination model of index pollution and data pollution, which combines the blacklist mechanism, the node selection strategy and other key factors of the effect of pollution, and introduced the concept of parallelism within the block, model the effect of pollution and pollution costs. Finally, we design and implement a system for high-performance file pollution, contaminated by a large number of experimental results, we analysis and verify the correctness of the hybrid pollution model, and calculate the indicator values of effect of pollution and pollution costs.更多还原