The Research On Search Algorithms And Trust Mechanism Based On P2P File Sharing System

The dispession of P2P technology is compatible to the protocol and structure of Internet, and it has strong adaptability and the ability of network services. With the rapid development of Internet network, the advantages of P2P technology have been further exploited. Because of the large-scale of P2P network, the instability of the spread of the node, too much data types, in order to further expend the application of the P2P networks, we need to design effective search algorithms and the trust mechanism. Among all the applications of P2P technolgy, the file sharing system is the most widely used one. The anonymous, dynamical, open features of P2P network bring many problems to file sharing system. Based on the characters of P2P network, this thesis makes a deep research and analysis of the existing trust models and incentives mechanism, modified the existing trust mechanisms, and proposed a CMARCH reputation based on assorted reputation value of P2P file sharing system. The main tasks are as follows:(1)This thesis gives a general analysis of the characters, the main applications of P2P network, the topology structure of P2P network, and compares the advantages and disadvantages of several topology structure of P2P network.(2)Researches the three categories search algorithm of P2P network. Bases on the problem of space waste of resources of RPM search algorithm, proposes RCPM search algorithm which is building pointer circle. The simulation experiment indicates the RCPM search algorithm not only to ensure the efficient search for RPM, low traffic volume on the basis of the advantages, but also reduces the space resource consumption.(3)Based on the problems of P2P file sharing system, analysis of the existing four categories of solutions, compares the advantages and disadvantages of them, based on the MARCH mechanism, proposes a CMARCH reputation mechanism which is a combination of Category, Money and Reputation sCHemes, in order to solve the "node reputation's credible lose" that brought about from only one reputation value corresponds to a node. The mechanism sets the reputation value for each resource category respectively based on the resource type provided by each node. CMARCH mechanism to ensure to resolve malicious node conspiracy, free riders on the basis of such issues, further reducing the overpaid money ratio and failed transaction ratio, to ensure the success of the transaction between nodes, to promote the diversification of the node resources of the P2P file sharing systems, and the results were verified via simulation experiment.