Research On Vulnerability Analysis For Dark Network Based On Tor

As the Internet increasingly affects in-depth every aspect of people's daily life, and meets the requirements of different people, people's identity information is more and more sensitive. So, as the study of anonymous communication attracts more and more individuals and institutions, different mechanism of anonymous communication system has been designed. Tor is currently the most popular and practical anonymous communication system, it adopts the second generation of onion routing technology, which could fully guarantee the user's anonymity.Tor Hidden Service protocol, can provide anonymity protection, which is not addressed in the Tor anonymous communication system. By establishing a Hidden Server, Tor not only provides one-way anonymity in the regular communication links, but also provides two-way anonymity in the unconventional six-jump communication links. That is, service providers and service requesters could conceal their indentity in the process of the whole communication, Dark network, which is based on Tor utilizes the protocol, to protect users' privacy.This thesis first introduces the concept of anonymous communication, studys the origin and development of anonymous communication,different mechanisms of anonymous communication system to summarize advantages and disadvantages of the exsiting mechanisms, including agent-based mechanism, mix-node-based mechanism, broadcast and multicast mechanism.Secondly, this thesis briefly introduces process of the Tor anonymous communication system, the packet structure and communication protocol. Then, the paper elaborates or the origin, structure and process of the Tor Hiddenservice.Thirdly, this paper briefly introduces the dark network which is based on Tor, and points the weakness of the dark network in the aspect of network structure and node slection strategy. Then, the paper shows the vulnerabilty of the dark network for the conspiracy attack, verification attack, circuit fingerprinting attack and traffic correlation attack. Some advices for the improvement of dark network protocol are proposed in the paper, including mergering redundant link, ordering data flow, eliminating correlation information, filling interfere with traffic.Finally, this thesis proposes a method to improve and control the communication link in the dark network for the weak dating node, and builds Tor-based private network and Hidden Service Server, sets the related parameters, conducts experiment toverify the effectiveness of the communication link control method.