Network Security Anonymity And Authenticity Of Documents

Peer-to-Peer Network is very popular in the recent years. The searching and downloading mechanism for files is always the hot spot on this technology.But a series of security problems that need to resovle urgently appeared because of the openness and autonomy of Peer-to-Peer Network.Among these problems,anonymity and file authentication receive less attention relatively.This dissertation lays the emphases on the issues of anonymity and file authentication in Peer-to-Peer system.Firstly, this dissertation introduces the background and application fields of Peer-to-Peer, illuminates research sitiuation of security in Peer-to-Peer.Then the searching and downloading mechanisms of there typical Peer-to-Peer models are compared and analyzed.This dissertation also analyzes the advantages of Peer-to-Peer model compared to Client/Server model and sums up main characteristics of Peer-to-Peer model.Secondly, seven aspects of security problems in Peer-to-Peer are discussed, especially the anonymity issue and its related technologies. Then, this dissertation improves searching and downloading mechanism of Freenet by IP multicast.After improving, the mechanism eliminated two shortcomings of original mechanism.Meanwhile,it ensures the anonymity of sender and receiver.Thirdly, four main criterias of authenticating files are displayed. Then,searching and downloading mechanism of the most typical file authentication protocol for Peer-to-Peer——XREP is minutely analyzed and researched.After that,a Peer-to-Peer file authentication mechanism based on Onion Routing and simple poll with on value is designed.The process of searching,polling and downloading in this mechanism is analyzed in detail. The most important feature of this mechanism is that it can provide anonymity of initiator, anonymity of voter, anonymity of agent node and anonymity of file supplier.