Research On Anonymous Communication Based On Tor Network

With the development of information technology, Internet has been involved in most people lives, and more and more people lifestyle depeond on Internet. E-commonce has become the common phenomenon in the society, including e-voting, e-banking, e-trading, e-shopping, e-auction and so on.Relative to the normal network communication, e-commerce applications has its own special communication security requirements. Based on the protection of tranditional information security attributes (confidentiality, integrity and authenticity), There is growing concern about how to protect the communication user identity information, how to protect the network service identity information, and how to resist the communication traffic analysis. That is to say people begin to concern about e-commerce applications communication anonymity.In this paper, with the new communication security requirements, we research on anonymous communication based on Tor network, which is the most successful anonymous communication system. Firstly we outline the research background and the basic principles of the anonymous communication, and introduce the main anonymous communication systems. Then we completely analyze the Tor network protocol, the Tor network status and the Tor network challenges. Based on these analyses, we put our research focus on the following three key issues:how to improve anonymity level and performance level of Tor network circuit building, how to build Tor network trust mechanism, how to build Tor network anti-misbehave mechanism, and propose the new protocols in these three research fields. In addition we also present a quantitative methmatic evaluation and proof to the new protocols which we provide in these three fields.The first key issue, through the analysis of current Tor network Circuit Building Protocol, we propose the new Random Walk-based Circuit Building Protocol.Tor network is a low-latency circuit switching anonymous communication service. The user needs to build anonymous communication circuit, and then use this circuit to transmit anonymously application data. So circuit building is one of the core content of Tor network. In this research area, we clearly investigate the process and the problems of the current Circuit Building Protocol, and then propose Random Walk-based Circuit Building Protocol which is based on random walk algorithm and the user-selectable relay node selection algorithm. Finally we present the the qualitative and quantitative analysis to the new protocol, and obtain the corresponding result:Compared with current Circuit Building Protocol, Random Walk-based Circuit Building Protocol provides the better communication anonymity, the same transmission performance level and the better user experience.The second key issue, through the analysis of current Tor network directory service and against Tor network attack behavior, we propose the new evaluation system to address the challenge which is how evaluate the Tor network credibility.Tor network trust mechanism has become one of the challenges of the Tor network development. So Tor network requires a reasonable, efficient, safe trust evaluation system to improve the system nodes credibility, to reduce the system vulnerability degree, to increase the user experience. In this research area, we clearly investigate current directory service and against Tor network attack types, and lead to the Tor network evaluation system requirements. Then we propose systematic evaluation system. The evaluation system address two key issues:how to asses relay node and how to return relay node information which the user needs. Finally we present the the qualitative analysis to the new protocol, and obtain the corresponding result:the Tor network evaluation system provides the better communication anonymity, and promotes the overall Tor performance to the extent.The third key issue, through the analysis of current Tor network malicious behavior and exit policies, we propose the new anti-misbehavior system to address the challenge which is how to improve the ability against malicious behavior.The ability against malicious behavior has become one of the challenges of the Tor network development. So Tor network requires a reasonable, efficient, safe anti-misbehavior system to improve the ability against malicious behavior, and promote Tor network healthy development. In this research area, we clearly investigate current Tor network malicious behavior and exit policy. Based on the investigation we propose anti-misbehavior system. The system includes two blacklists: global blacklist and local blacklist, and three protocols:Reporting Misbehavior Protocol, Building Global Blacklist Protocol and Blocking Misbehavior Users Protocol. In addition we also present the qualitative evaluation to the new protocol, and obtain the corresponding result:through our evaluation, we think compared with the current exit policies, anti-misbehavior system provides better user experience better anti-misbehavior performance, and the same transmission performance level.Finally, according to quantitative anonymity assessment method based on re-routing characteristics, we present the quantitative deduction and calculation to the current Tor network and Enhanced Tor network based on new protocol and new system within the scope of Tor network threat mode, and obtain corresponding anonymity value. Then we compare and analyze the anonymity value of the current Tor networt and the anonymity value of the Enhanced Tor network, obtain the final conclusion:the anonymity of Enhanced Tor network based on new protocol and system is better than the anonymity of current Tor network.