A Systematic Review of Network Flow Watermarking In Anonymity Systems

Tianbo Lu,Rui Guo,Lingling Zhao,Yang Li 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.3

With the rapid development of internet technology, the connection between man and internet is closer and closer. When people is communicating with others through internet, some malicious intruders may want to eavesdrop or peep the communicators. In order to evade being watching, people use anonymous communication systems to communicate. The anonymity system can encrypt the content of communication and the identity of the communicators. But if the communicators want to know who is talking to them at the other end, they must correlate the outgoing and incoming flows to identify a host or a person. As an active traffic analysis approach, network flow watermarking technology can detect the correlation of flows, and then make the anonymous communicators accountable. While network flow watermarking technology achieves good detecting rate and low false positive rate, it could be an effective way to trace the communication connections and supervise anonymous communication. So it is a widely used way for tracing in anonymity systems. In this paper, we introduce some different schemes of network flow watermarking in anonymity systems and discuss some attacks against it. Finally, a conclusion will be given.

Towards Attacks and Defenses of Anonymous Communication Systems

Tianbo Lu,Puxin Yao1,Lingling Zhao,Yang Li,Feng Xie,Yamei Xia 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.1

Anonymous communication system has been hot topic in the field of information security, and attack techniques against anonymous systems are endless. This paper first classifies and summarizes the study of attacks against anonymous communication system in recent years, then analyzes the trend of the research on different attack technologies; secondly, it provides a comparative analysis of defense capability the mainstream anonymous communication system to the various attacks; Finally, combining the advantages and disadvantages of different systems, the authors propose an improved node selection and router forwarding algorithms for anonymous communication systems, and design an architecture of anonymous communications software based on the algorithm.

A Framework for Analyzing Anonymous Network Topology

Tianbo Lu,Shixian Du,Yang Li,Peiyuan Dong,Xiaoyan Zhang 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.4

Nowadays, Internet privacy becomes more and more important and sensitive, and has been one of the latest buzz words to hit the Internet world. In response to protect the privacy of Internet users, a variety of privacy enhancing technologies (PETs) have emerged. As one of privacy enhancing technologies, anonymous communication has been extensively studied from various aspects by researchers. Node churn is frequent in anonymous network, which make it difficult to maintain a stable network topology, therefore it is necessary to get more insight into the overall anonymous network topology. In this work, in order to better grasp the present situation of research, we investigate existing organizations and universities which study anonymous communication from the perspective of network topology, and related projects. Then we survey related papers to anonymous communication published in recent years, which focus on the analysis of node selection (especially in the Tor). In addition, we present a framework of anonymous communication network topology, and a visual illustration of this analysis that shows the progression of the research of network topology and node discovery in anonymous communication. Finally, some related problems and follow-up study are presented to be studied deeply in future.

F-Crowds : An Anonymity Scheme for P2P File-Sharing

Tianbo Lu,Xinyuan Zhang,Xiaofeng Du,Yang Li 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.6

The traditional encryption methods pay more attention to the confidentiality of the message content, but ignore the protection of identity information to the communicating parties. By encrypting, the contents of the communication acquired by attackers became relatively difficult, but they can still found the identity information of the two sides to communicate easily because in the TCP / IP protocol, the sender and receiver of the message are exposed. The anonymity communication technology, is used to solve this problem. The first anonymity communication technology can date back to 1981, Chaum proposed MIX [1] which is a very important technology for reference by a number of researchers of anonymity communication. The rapid development of the Internet has made things convenience to people, but also led to more personal information exposed to the public. As a result, a growing number of areas that required anonymity communication technology to protect the user's privacy. P2P file-sharing is not exception. P2P is undoubtedly the most popular way for file-sharing, but popular P2P file-sharing protocols, such as BitTorrent, can’t provide users anonymity communication service. Many people choose to build upon existing anonymous communication tools, such as Tor, to achieve anonymous P2P file transfer, but Tor primarily provides anonymous service for web browsing, instant message or other low latency applications. A large number of P2P file traffic will seriously threaten the service of Tor. Therefore, the anonymity communication service specifically for P2P file sharing system is very important. In this paper, we presents an anonymity communication scheme specifically for P2P file-sharing networks called F-Crowds which based on Crowds [2] to provide an adjustable anonymity service for P2P file-sharing.

Towards a Comprehensive Analysis of Crowds Anonymity System

Tianbo Lu,Xinyuan Zhang,Xiaofeng Du,Yang Li 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.7

There is an increasing command for anonymity in network. Crowds[1] is an popular anonymity system proposed by Michael K. Reiter and Aviel D. Rubin which main idea behind it is hiding users’ identities by routing their packets randomly within a group of similar users. Crowds can provides sender anonymity and also has an advantage that the computation load of relay nodes is very small but it does not protect the identity of the receiver. This paper presents an overview on Crowds and introduces the development of Crowds from the following aspects: anonymity analysis, application especially the application in P2P and the performance. We summarize the work about anonymity analysis based on Crowds and divide them into receiver analysis, probabilistic behavior, attack and anonymity proof. Crowds is high efficient but it can’t resist the global attack, therefore, to meet the needs of the different levels of anonymity, there is a vast body of anonymity literature concerned with anonymity analysis, for example, Crowds can’t provide receiver anonymity but receiver anonymity is important in many cases, so many work extending the Crowds system from sender anonymity only to sender and receiver anonymity. In addition to the analysis, we also summarize the applications of Crowds. Undoubtedly, it is widely used in P2P. We also give an overlook of the performance of Crowds.

H∞ Filtering Problem of Singular Systems with Uncertainties in the Difference Matrix

Tianbo Xu,Qing-Ling Zhang,Feng Zhao 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.3

This study considers H∞ filtering problems for continuous-time singular systems with norm-boundeduncertainties in the difference matrix. Under the condition that the difference matrix is rank-variant for all admissibleuncertainties, the robustness analysis problem under consideration falls into two cases: right-singular case andleft-singular case. By using a state augmentation technique, Based on two cases, H∞ filtering problem is considered,and a new H∞ filter design result is summarized in this paper. Finally, illustrative examples show that the proposedconditions are effective for the singular systems with norm-bounded uncertainties in the difference matrix.

NSDA : A Novel Node Selecting Optimal Algorithm Based on Dijkstra

Tianbo Lu,Jiao Zhang,Lingling Zhao,Yang Li,Xiaoyan Zhang 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.6

This paper first represent the basic conceptions of anonymous communication, then introduce the fundamentals in Anonymous Communication. Afterwards, we went deep to the classification of anonymous network topological, therefore we could get a better understanding on P2P anonymous communication system. We also systematically analyzes the existing node-select algorithms. Furthermore, we propose and implement a new node selection algorithm based on Dijkstra algorithm, named NSDA algorithm. We give a belief description about the backgrounds and design of NSDA Algorithm. The algorithm can combine the node properties with link properties to select node, which can adjust the system performancing and anonymity. In order to evaluate the NSDA algorithm, we have done experiments in Network Simulator 3, and we also explain the reason why we choose Network Simulator 3 as the simulate tool. In the end, we analyze the characteristics of NSDA algorithm according to the results of experiments.

A Security Architecture in Cyber-Physical Systems : Security Theories, Analysis, Simulation and Application Fields

Tianbo Lu,Jiaxi Lin,Lingling Zhao,Yang Li,Yong Peng 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.7

Governments, companies, universities and research institutes are pushing the research and development of cyber-physical systems (CPS). However, the development of cyber-physical systems is constrained by security factors. According to this situation, this paper put forward a CPS security model, which contains security objectives, basic theories, simulation, and CPS framework, summarizes security attacks to cyber-physical systems as a theoretical reference for the study of cyber–physical systems and to provide useful security defense. Based on the cyber-physical systems framework, the paper classifies attacks for the execution layer, transport layer and control layer. The execution layer attacks include security attacks for nodes such as sensors and actuators. Transport layer attacks include data leakage or damage and security issues during massive data integration. Control layer attacks include the loss of user privacy, incorrect access control policies and inadequate security standards. This paper gives security defenses and recommendations for all types of security attacks. Finally, this paper introduces categorizations of CPS application fields and explores their relationships.

Security Model for Sensitive Information Systems and Its Applications in Sensor Networks

Tianbo Lu,Xiaobo Guo,Lingling Zhao,Yang Li,Peng Lin,Binxing Fang 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.5

The study of security models for sensitive information systems has been taken on for years, but still lag far away behind the progress of information security practice. During this century, the thought of seeking the system security to the source of system development lifecycle received huge improvement in the system and software assurance domain. This paper firstly expounds the understanding of information security by illustrating information security study development progress since pre-computer age and presents a description of cyberspace and cyberization security by summarizing the status quo of cyberization. Then a security model called PDRL, which includes six core security attributes of sensitive information systems, is proposed to protect the security of sensitive information systems in the whole system life-cycle. At last, this paper probes into further discussion about controllability attribute and proposes a controllability model in sensitive sensor networks, followed by a probability computing formula and the example for computing the controllability of sensitive sensor networks. By dividing each single element of sensitive information and each element-related operation into a corresponding classification, this paper makes a reasonable description of the quantitative description about controllability.

Regulatory Mechanism of MicroRNA-145 in the Pathogenesis of Acute Aortic Dissection

Tianbo Li,Chencheng Liu,Lingchao Liu,Han Xia,Yingbin Xiao,Xuefeng Wang,Yong Wang 연세대학교의과대학 2019 Yonsei medical journal Vol.60 No.4

Purpose: Previous studies have confirmed that microRNAs play important roles in the pathogenesis of acute aortic dissection(AAD). Here, we aimed to explore the role of miR-145 and its regulatory mechanism in the pathogenesis of AAD. Materials and Methods: AAD tissue samples were harvested from patients with aortic dissection and normal donors. Rat aorticvascular smooth muscle cells (VSMCs) were transfected with miR-145 mimic/inhibitor or negative control mimic/inhibitor. Geneand protein expression was measured in human aortic dissection tissue specimens and VSMCs by qRT-PCR and Western blot. Luciferasereporter assay was applied to verify whether connective tissue growth factor (CTGF) was a direct target of miR-145 inVSMCs. Methyl thiazolyl tetrazolium assay was used to detect VSMC viability. Results: miR-145 expression was downregulated in aortic dissection tissues and was associated with the survival of patients withAAD. Overexpression of miR-145 promoted VSMC proliferation and inhibited cell apoptosis. Moreover, CTGF, which was increasedin aortic dissection tissues, was decreased by miR-145 mimic and increased by miR-145 inhibitor. Furthermore, CTGF wasconfirmed as a target of miR-145 and could reverse the promotion effect of miR-145 on the progression of AAD. Conclusion: miR-145 suppressed the progression of AAD by targeting CTGF, suggesting that a miR-145/CTGF axis may provide apotential therapeutic target for AAD.