Research On Incentive Mechanism And Relation Theory In Anonymous Communication Systems

With the rapid progress of the Internet application, computer networks have been widely used as a tool of information transmission and communication. Concerns on security of network and privacy of communication have been grown. The content of information can be concealed by new better encryption, but the situation information of sender and/or receiver, and the communication modes cannot be concealed. That is, encryption cannot prevent adversaries from obtaining some value information by traffic analysis. In order to protect the privacy of communication from leaking in network communication, research on anonymous communication system is springing up.Firstly, we generalize the current status of research on anonymous communication; survey the current technologies of anonymous communication; summarize the attacks to anonymous communication systems and their characteristics; analyze the relation state-of- the-art of anonymity technologies and the next direction in these fields.Secondly, we put forward two anonymous communication strategies with respect to incentive mechanisms which can be used to avoid the free-riding phenomenon. One is payment mechanism. Another is reputation mechanism. We put forward a ripping scheme of electron coin which is suit for the next-top routing anonymous communication. An anonymous communication strategy based on the idea of fair exchange is proposed to promote the participants to provide service together. We analyze the number of coins which the sender uses to pay for those peers on the anonymous route, put forward a measure to rip coin and withdraw the surplus coins. Theoretical analysis shows that the system with the payment mechanism can promote the anonymous communication system more economy, and availably prevent participants profiting by collusion without loss the performance of system like Crowds. Moreover, the strategy avoids the probability of no upper bound for the length of route in the next-hop routing systems.At the same time, we also put forward a reputation mechanism which is suit for the peer-to-peer anonymous communication system. The reputation mechanism promotes the activity of members by members monitor the number of request each other. Another anonymous communication strategy based on the idea of differential service is proposed with respect to reputation mechanism in this paper. The mechanism declines the selfish member the value of reputation by monitor the messages frequency each other, and makes the members with different reputation obtaining different performance in system. Theory analysis and computation number show that these systems with reputation mechanism can guarantee the performance of normal members, punish with selfish members by decreasing their anonymity degree and their efficiency, and decline the free-riding problem caused by selfish members.Next, based to the character of self-organizing and structure in the structured Peer-to-Peer network, we put forward a rerouting-based anonymous communication scheme, which does not need an administrating node. Because of the opening character of overlay network, the relation on the expected value of rerouting path and forward probability, and the relation on the expected value of rerouting path and the number of hostility participant are analyzed in this paper. The calculation result demonstrates that descending forward probability makes the expected value of rerouting path decrease distinctly, therefore limits the communication delay. Then, the application of reputation mechanism in the structured Peer-to-Peer network is also researched, and some conclusions are drawed by theory analyzing and calculations.Finally, there is the phenomenon of untrustworthy and personate members maybe turn up in the anonymous communication system, we analyze a man-in-the-middle attack, which happen in the information transmission and cannot be discovered. We put forward a safe mechanism of bit commitment, which is respect to pseudo-random numbers and Hash function. We also put forward an active detection mechanism which can be used to detect the untrustworthy and/or personate member. Theoretical analyses show the mechanism can protects the data from man-in-the-middle attack during the transmission course; the active detection mechanism, which guarantees the anonymity of the active detector, can efficiently detect the untrustworthy and/or personate members.Our research on related techniques of incentive mechanism, anonymity system with no-administer node, and active detection in anonymous communication will not only complement the basic theories but also guide to set up better anonymity systems.