Research On Key Technologies In P2P Content Censorship

In recent years, P2P network that represented by P2P file sharing applicationsand P2P streaming media applications had gained rapid development, but at the sametime, some irregularities network resources also spread rapidly with P2P networkapplications, and caused a lot of networking and social problem. How to monitor P2Pcontent and information effectively has become an urgent key issue in P2Presearchfield.The regulatory actions for P2P content includes three key steps, resources andnode information collection, the options of management objectives as well as thecontrol of the spread of illegal resource. The collection of resources and nodeinformation is to collect the resources of target P2P system and it’s publishinformation and node information that based on regulatory objectives, the main waythat currently used is reptiles. The process of management objective selection isdistinguished normal and irregularities resources that based on the objectives andscope of the content management and the collection of resource and node information.Illegal resource dissemination control is the behavior to manage the spread of theselected target resources through technical and non-technical means, the current majormanagement strategies focused on reducing the accuracy of the index, and achieve itby publishing the wrong index information in P2P systems through the crawler system.However, the existing technology also has the following problems:1) With thedevelopment of P2P technology, some of the original data collection technology hasbeen unable to complete the task of data collection, such as the traditional port-basedmanagement methods; Moreover, for others such as DHT based new P2P systemarchitecture for data collection, the existing collection strategies exist obvious defects,such as poor comprehensiveness and inefficient;2) Only rely on the release ofresources information as a basis for judgment whether the resource violation, ignorethat the resource availability and the difference that the degree of concern that isbetween different resources influence on regulatory effect;3) The accuracy ofcurrently adopted strategy by poisoning the index have less effect because the featuresof resources or nodes could taken by ordinary users to distinguish the useable and theunusable. To solve those problems, through the study of distribution of P2P resources andthe actuality of P2P censorship, this dissertation has focused on the strategy of P2Pinformation gathering, the validity of resource and the mechanism of resource spreadand the way to dominate the propagation.Firstly, to improve the completety of metadata gathering in DHT-based systems,a Family-Resemblance based metadata snapshot strategy is proposed. Through thepartly similarity between two metadata, the snapshot strategy could continuouslyiterate by taken the unknown part from any known metadata. In a real DHT basedsystem where the strategy was deployed, about10million metadata was acquired byonly1search term, which proves the Family-Resemblance based strategy indirectly.Secondly, to increase the granularity of target selecting in censorship, a statisticalinference based resource validity differentiation is proposed. The relation between aresource and relatively metadata could be changed into the relation between twometadata, which is much easier to solve. Thus, a standard wilcoxon test could be usedto tell whether a series of resources is valid or not from the view of number ofmetadata. With this inference,1) A huge numbers of invalid resource could beexcluded from censorship target;2) By expending the oberservation, learing algorithmcould be taken to solve the target selecting procedure.Thirdly, to break the current limition in propagation control by inserting invalidcopies or metadatas, an information theory channel model based mechanism isproposed. Though this channel model based mechanis, two obvious points of view tocontrol the resource spread are proposed:1) Currently adopted control strategy is theway to redistribute the information source; and2) A series of features of resourcesand nodes could highly affect the choice of ordinary users. Both are aim to decreaseI(X; Y) which is the factor to measure the effect of propagation control. At last, anmultivariable regression is taken to prove that the historical download times and thesize of a file are the key factors in P2P file sharing systems to affect users’ choices.Besides, this analysis based on information theory gives the theorical evidence ofcurrent stategy and proposes a new way to implement the propagation control.