Visible to the public Biblio

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2023-09-01
Paschal Mgembe, Innocent, Ladislaus Msongaleli, Dawson, Chaundhary, Naveen Kumar.  2022.  Progressive Standard Operating Procedures for Darkweb Forensics Investigation. 2022 10th International Symposium on Digital Forensics and Security (ISDFS). :1—3.
With the advent of information and communication technology, the digital space is becoming a playing ground for criminal activities. Criminals typically prefer darkness or a hidden place to perform their illegal activities in a real-world while sometimes covering their face to avoid being exposed and getting caught. The same applies in a digital world where criminals prefer features which provide anonymity or hidden features to perform illegal activities. It is from this spirit the Darkweb is attracting all kinds of criminal activities conducted over the Internet such as selling drugs, illegal weapons, child pornography, assassination for hire, hackers for hire, and selling of malicious exploits, to mention a few. Although the anonymity offered by Darkweb can be exploited as a tool to arrest criminals involved in cybercrime, an in-depth research is needed to advance criminal investigation on Darkweb. Analysis of illegal activities conducted in Darkweb is in its infancy and faces several challenges like lack of standard operating procedures. This study proposes progressive standard operating procedures (SOPs) for Darkweb forensics investigation. We provide the four stages of SOP for Darkweb investigation. The proposed SOP consists of the following stages; identification and profiling, discovery, acquisition and preservation, and the last stage is analysis and reporting. In each stage, we consider the objectives, tools and expected results of that particular stage. Careful consideration of this SOP revealed promising results in the Darkweb investigation.
2022-04-12
K M, Akshobhya.  2021.  Machine learning for anonymous traffic detection and classification. 2021 11th International Conference on Cloud Computing, Data Science Engineering (Confluence). :942—947.
Anonymity is one of the biggest concerns in web security and traffic management. Though web users are concerned about privacy and security various methods are being adopted in making the web more vulnerable. Browsing the web anonymously not only threatens the integrity but also questions the motive of such activity. It is important to classify the network traffic and prevent source and destination from hiding with each other unless it is for benign activity. The paper proposes various methods to classify the dark web at different levels or hierarchies. Various preprocessing techniques are proposed for feature selection and dimensionality reduction. Anon17 dataset is used for training and testing the model. Three levels of classification are proposed in the paper based on the network, traffic type, and application.
Mahor, Vinod, Rawat, Romil, Kumar, Anil, Chouhan, Mukesh, Shaw, Rabindra Nath, Ghosh, Ankush.  2021.  Cyber Warfare Threat Categorization on CPS by Dark Web Terrorist. 2021 IEEE 4th International Conference on Computing, Power and Communication Technologies (GUCON). :1—6.
The Industrial Internet of Things (IIoT) also referred as Cyber Physical Systems (CPS) as critical elements, expected to play a key role in Industry 4.0 and always been vulnerable to cyber-attacks and vulnerabilities. Terrorists use cyber vulnerability as weapons for mass destruction. The dark web's strong transparency and hard-to-track systems offer a safe haven for criminal activity. On the dark web (DW), there is a wide variety of illicit material that is posted regularly. For supervised training, large-scale web pages are used in traditional DW categorization. However, new study is being hampered by the impossibility of gathering sufficiently illicit DW material and the time spent manually tagging web pages. We suggest a system for accurately classifying criminal activity on the DW in this article. Rather than depending on the vast DW training package, we used authorized regulatory to various types of illicit activity for training Machine Learning (ML) classifiers and get appreciable categorization results. Espionage, Sabotage, Electrical power grid, Propaganda and Economic disruption are the cyber warfare motivations and We choose appropriate data from the open source links for supervised Learning and run a categorization experiment on the illicit material obtained from the actual DW. The results shows that in the experimental setting, using TF-IDF function extraction and a AdaBoost classifier, we were able to achieve an accuracy of 0.942. Our method enables the researchers and System authoritarian agency to verify if their DW corpus includes such illicit activity depending on the applicable rules of the illicit categories they are interested in, allowing them to identify and track possible illicit websites in real time. Because broad training set and expert-supplied seed keywords are not required, this categorization approach offers another option for defining illicit activities on the DW.
2021-01-28
Salib, E. H., Aboutabl, M. S..  2020.  Hands-on Undergraduate Labs on Anonymity Cryptographic Algorithms. 2020 IEEE Frontiers in Education Conference (FIE). :1—9.

This is an innovative practice full paper. In past projects, we have successfully used a private TOR (anonymity network) platform that enabled our students to explore the end-to-end inner workings of the TOR anonymity network through a number of controlled hands-on lab assignments. These have saisfied the needs of curriculum focusing on networking functions and algorithms. To be able to extend the use and application of the private TOR platform into cryptography courses, there is a desperate need to enhance the platform to allow the development of hands-on lab assignments on the cryptographic algorithms and methods utilized in the creation of TOR secure connections and end-to-end circuits for anonymity.In tackling this challenge, and since TOR is open source software, we identify the cryptographic functions called by the TOR algorithms in the process of establishing TLS connections and creating end-to-end TOR circuits as well tearing them down. We instrumented these functions with the appropriate code to log the cryptographic keys dynamically created at all nodes involved in the creation of the end to end circuit between the Client and the exit relay (connected to the target server).We implemented a set of pedagogical lab assignments on a private TOR platform and present them in this paper. Using these assignments, students are able to investigate and validate the cryptographic procedures applied in the establishment of the initial TLS connection, the creation of the first leg of a TOR circuit, as well as extending the circuit through additional relays (at least two relays). More advanced assignments are created to challenge the students to unwrap the traffic sent from the Client to the exit relay at all onion skin layers and compare it with the actual traffic delivered to the target server.

2021-01-15
Korolev, D., Frolov, A., Babalova, I..  2020.  Classification of Websites Based on the Content and Features of Sites in Onion Space. 2020 IEEE Conference of Russian Young Researchers in Electrical and Electronic Engineering (EIConRus). :1680—1683.
This paper describes a method for classifying onion sites. According to the results of the research, the most spread model of site in onion space is built. To create such a model, a specially trained neural network is used. The classification of neural network is based on five different categories such as using authentication system, corporate email, readable URL, feedback and type of onion-site. The statistics of the most spread types of websites in Dark Net are given.
2020-08-13
Basyoni, Lamiaa, Erbad, Aiman, Alsabah, Mashael, Fetais, Noora, Guizani, Mohsen.  2019.  Empirical Performance Evaluation of QUIC Protocol for Tor Anonymity Network. 2019 15th International Wireless Communications Mobile Computing Conference (IWCMC). :635—642.
Tor's anonymity network is one of the most widely used anonymity networks online, it consists of thousands of routers run by volunteers. Tor preserves the anonymity of its users by relaying the traffic through a number of routers (called onion routers) forming a circuit. The current design of Tor's transport layer suffers from a number of problems affecting the performance of the network. Several researches proposed changes in the transport design in order to eliminate the effect of these problems and improve the performance of Tor's network. In this paper. we propose "QuicTor", an improvement to the transport layer of Tor's network by using Google's protocol "QUIC" instead of TCP. QUIC was mainly developed to eliminate TCP's latency introduced from the handshaking delays and the head-of-line blocking problem. We provide an empirical evaluation of our proposed design and compare it to two other proposed designs, IMUX and PCTCP. We show that QuicTor significantly enhances the performance of Tor's network.
2020-07-10
Koch, Robert.  2019.  Hidden in the Shadow: The Dark Web - A Growing Risk for Military Operations? 2019 11th International Conference on Cyber Conflict (CyCon). 900:1—24.

A multitude of leaked data can be purchased through the Dark Web nowadays. Recent reports highlight that the largest footprints of leaked data, which range from employee passwords to intellectual property, are linked to governmental institutions. According to OWL Cybersecurity, the US Navy is most affected. Thinking of leaked data like personal files, this can have a severe impact. For example, it can be the cornerstone for the start of sophisticated social engineering attacks, for getting credentials for illegal system access or installing malicious code in the target network. If personally identifiable information or sensitive data, access plans, strategies or intellectual property are traded on the Dark Web, this could pose a threat to the armed forces. The actual impact, role, and dimension of information treated in the Dark Web are rarely analysed. Is the available data authentic and useful? Can it endanger the capabilities of armed forces? These questions are even more challenging, as several well-known cases of deanonymization have been published over recent years, raising the question whether somebody really would use the Dark Web to sell highly sensitive information. In contrast, fake offers from scammers can be found regularly, only set up to cheat possible buyers. A victim of illegal offers on the Dark Web will typically not go to the police. The paper analyses the technical base of the Dark Web and examines possibilities of deanonymization. After an analysis of Dark Web marketplaces and the articles traded there, a discussion of the potential risks to military operations will be used to identify recommendations on how to minimize the risk. The analysis concludes that surveillance of the Dark Web is necessary to increase the chance of identifying sensitive information early; but actually the `open' internet, the surface web and the Deep Web, poses the more important risk factor, as it is - in practice - more difficult to surveil than the Dark Web, and only a small share of breached information is traded on the latter.

Yang, Ying, Yang, Lina, Yang, Meihong, Yu, Huanhuan, Zhu, Guichun, Chen, Zhenya, Chen, Lijuan.  2019.  Dark web forum correlation analysis research. 2019 IEEE 8th Joint International Information Technology and Artificial Intelligence Conference (ITAIC). :1216—1220.

With the rapid development of the Internet, the dark network has also been widely used in the Internet [1]. Due to the anonymity of the dark network, many illegal elements have committed illegal crimes on the dark. It is difficult for law enforcement officials to track the identity of these cyber criminals using traditional network survey techniques based on IP addresses [2]. The threat information is mainly from the dark web forum and the dark web market. In this paper, we introduce the current mainstream dark network communication system TOR and develop a visual dark web forum post association analysis system to graphically display the relationship between various forum messages and posters, and help law enforcement officers to explore deep levels. Clues to analyze crimes in the dark network.

Yang, Ying, Yu, Huanhuan, Yang, Lina, Yang, Ming, Chen, Lijuan, Zhu, Guichun, Wen, Liqiang.  2019.  Hadoop-based Dark Web Threat Intelligence Analysis Framework. 2019 IEEE 3rd Advanced Information Management, Communicates, Electronic and Automation Control Conference (IMCEC). :1088—1091.

With the development of network services and people's privacy requirements continue to increase. On the basis of providing anonymous user communication, it is necessary to protect the anonymity of the server. At the same time, there are many threatening crime messages in the dark network. However, many scholars lack the ability or expertise to conduct research on dark-net threat intelligence. Therefore, this paper designs a framework based on Hadoop is hidden threat intelligence. The framework uses HDFS as the underlying storage system to build a HBase-based distributed database to store and manage threat intelligence information. According to the heterogeneous type of the forum, the web crawler is used to collect data through the anonymous TOR tool. The framework is used to identify the characteristics of key dark network criminal networks, which is the basis for the later dark network research.

2020-07-06
Attarian, Reyhane, Hashemi, Sattar.  2019.  Investigating the Streaming Algorithms Usage in Website Fingerprinting Attack Against Tor Privacy Enhancing Technology. 2019 16th International ISC (Iranian Society of Cryptology) Conference on Information Security and Cryptology (ISCISC). :33–38.
Website fingerprinting attack is a kind of traffic analysis attack that aims to identify the URL of visited websites using the Tor browser. Previous website fingerprinting attacks were based on batch learning methods which assumed that the traffic traces of each website are independent and generated from the stationary probability distribution. But, in realistic scenarios, the websites' concepts can change over time (dynamic websites) that is known as concept drift. To deal with data whose distribution change over time, the classifier model must update its model permanently and be adaptive to concept drift. Streaming algorithms are dynamic models that have these features and lead us to make a comparison of various representative data stream classification algorithms for website fingerprinting. Given to our experiments and results, by considering streaming algorithms along with statistical flow-based network traffic features, the accuracy grows significantly.
2020-01-02
Gallagher, Kevin, Patil, Sameer, Dolan-Gavitt, Brendan, McCoy, Damon, Memon, Nasir.  2018.  Peeling the Onion's User Experience Layer: Examining Naturalistic Use of the Tor Browser. Proceedings of the 2018 ACM SIGSAC Conference on Computer and Communications Security. :1290–1305.

The strength of an anonymity system depends on the number of users. Therefore, User eXperience (UX) and usability of these systems is of critical importance for boosting adoption and use. To this end, we carried out a study with 19 non-expert participants to investigate how users experience routine Web browsing via the Tor Browser, focusing particularly on encountered problems and frustrations. Using a mixed-methods quantitative and qualitative approach to study one week of naturalistic use of the Tor Browser, we uncovered a variety of UX issues, such as broken Web sites, latency, lack of common browsing conveniences, differential treatment of Tor traffic, incorrect geolocation, operational opacity, etc. We applied this insight to suggest a number of UX improvements that could mitigate the issues and reduce user frustration when using the Tor Browser.

2019-10-30
Jansen, Rob, Traudt, Matthew, Hopper, Nicholas.  2018.  Privacy-Preserving Dynamic Learning of Tor Network Traffic. Proceedings of the 2018 ACM SIGSAC Conference on Computer and Communications Security. :1944-1961.

Experimentation tools facilitate exploration of Tor performance and security research problems and allow researchers to safely and privately conduct Tor experiments without risking harm to real Tor users. However, researchers using these tools configure them to generate network traffic based on simplifying assumptions and outdated measurements and without understanding the efficacy of their configuration choices. In this work, we design a novel technique for dynamically learning Tor network traffic models using hidden Markov modeling and privacy-preserving measurement techniques. We conduct a safe but detailed measurement study of Tor using 17 relays (\textasciitilde2% of Tor bandwidth) over the course of 6 months, measuring general statistics and models that can be used to generate a sequence of streams and packets. We show how our measurement results and traffic models can be used to generate traffic flows in private Tor networks and how our models are more realistic than standard and alternative network traffic generation\textasciitildemethods.

2019-04-05
Huang, M. Chiu, Wan, Y., Chiang, C., Wang, S..  2018.  Tor Browser Forensics in Exploring Invisible Evidence. 2018 IEEE International Conference on Systems, Man, and Cybernetics (SMC). :3909-3914.
Given the high frequency of information security incidents, feeling that we may soon become innocent victims of these events may be justified. Perpetrators of information security offenses take advantage of several methods to leave no evidence of their crimes, and this pattern of hiding tracks has caused difficulties for investigators searching for digital evidence. Use of the onion router (Tor) is a common way for criminals to conceal their identities and tracks. This paper aims to explain the composition and operation of onion routing; we conduct a forensic experiment to detect the use of the Tor browser and compare several browser modes, including incognito and normal. Through the experimental method described in this paper, investigators can learn to identify perpetrators of Internet crimes, which will be helpful in future endeavors in digital forensics.
Matyunin, Nikolay, Anagnostopoulos, Nikolaos A., Boukoros, Spyros, Heinrich, Markus, Schaller, André, Kolinichenko, Maksim, Katzenbeisser, Stefan.  2018.  Tracking Private Browsing Sessions Using CPU-Based Covert Channels. Proceedings of the 11th ACM Conference on Security & Privacy in Wireless and Mobile Networks. :63-74.

In this paper we examine the use of covert channels based on CPU load in order to achieve persistent user identification through browser sessions. In particular, we demonstrate that an HTML5 video, a GIF image, or CSS animations on a webpage can be used to force the CPU to produce a sequence of distinct load levels, even without JavaScript or any client-side code. These load levels can be then captured either by another browsing session, running on the same or a different browser in parallel to the browsing session we want to identify, or by a malicious app installed on the device. To get a good estimation of the CPU load caused by the target session, the receiver can observe system statistics about CPU activity (app), or constantly measure time it takes to execute a known code segment (app and browser). Furthermore, for mobile devices we propose a sensor-based approach to estimate the CPU load, based on exploiting disturbances of the magnetometer sensor data caused by the high CPU activity. Captured loads can be decoded and translated into an identifying bit string, which is transmitted back to the attacker. Due to the way loads are produced, these methods are applicable even in highly restrictive browsers, such as the Tor Browser, and run unnoticeably to the end user. Therefore, unlike existing ways of web tracking, our methods circumvent most of the existing countermeasures, as they store the identifying information outside the browsing session being targeted. Finally, we also thoroughly evaluate and assess each presented method of generating and receiving the signal, and provide an overview of potential countermeasures.

2019-01-31
Li, Shuai, Guo, Huajun, Hopper, Nicholas.  2018.  Measuring Information Leakage in Website Fingerprinting Attacks and Defenses. Proceedings of the 2018 ACM SIGSAC Conference on Computer and Communications Security. :1977–1992.

Tor provides low-latency anonymous and uncensored network access against a local or network adversary. Due to the design choice to minimize traffic overhead (and increase the pool of potential users) Tor allows some information about the client's connections to leak. Attacks using (features extracted from) this information to infer the website a user visits are called Website Fingerprinting (WF) attacks. We develop a methodology and tools to measure the amount of leaked information about a website. We apply this tool to a comprehensive set of features extracted from a large set of websites and WF defense mechanisms, allowing us to make more fine-grained observations about WF attacks and defenses.

Shahbar, K., Zincir-Heywood, A. N..  2018.  How Far Can We Push Flow Analysis to Identify Encrypted Anonymity Network Traffic? NOMS 2018 - 2018 IEEE/IFIP Network Operations and Management Symposium. :1–6.

Anonymity networks provide privacy to the users by relaying their data to multiple destinations in order to reach the final destination anonymously. Multilayer of encryption is used to protect the users' privacy from attacks or even from the operators of the stations. In this research, we showed how flow analysis could be used to identify encrypted anonymity network traffic under four scenarios: (i) Identifying anonymity networks compared to normal background traffic; (ii) Identifying the type of applications used on the anonymity networks; (iii) Identifying traffic flow behaviors of the anonymity network users; and (iv) Identifying / profiling the users on an anonymity network based on the traffic flow behavior. In order to study these, we employ a machine learning based flow analysis approach and explore how far we can push such an approach.

2018-09-12
Montieri, A., Ciuonzo, D., Aceto, G., Pescape, A..  2017.  Anonymity Services Tor, I2P, JonDonym: Classifying in the Dark. 2017 29th International Teletraffic Congress (ITC 29). 1:81–89.

Traffic classification, i.e. associating network traffic to the application that generated it, is an important tool for several tasks, spanning on different fields (security, management, traffic engineering, R&D). This process is challenged by applications that preserve Internet users' privacy by encrypting the communication content, and even more by anonymity tools, additionally hiding the source, the destination, and the nature of the communication. In this paper, leveraging a public dataset released in 2017, we provide (repeatable) classification results with the aim of investigating to what degree the specific anonymity tool (and the traffic it hides) can be identified, when compared to the traffic of the other considered anonymity tools, using machine learning approaches based on the sole statistical features. To this end, four classifiers are trained and tested on the dataset: (i) Naïve Bayes, (ii) Bayesian Network, (iii) C4.5, and (iv) Random Forest. Results show that the three considered anonymity networks (Tor, I2P, JonDonym) can be easily distinguished (with an accuracy of 99.99%), telling even the specific application generating the traffic (with an accuracy of 98.00%).

2018-05-02
Friebe, Sebastian, Florian, Martin.  2017.  DPS-Discuss: Demonstrating Decentralized, Pseudonymous, Sybil-resistant Communication. Proceedings of the SIGCOMM Posters and Demos. :74–75.
A current trend on the Internet is the increasing surveillance of its users. A few big service providers have divided most of the user-facing Internet between them, observing and recording the activities of their users to increase profits. Additionally, government agencies have been found to practice mass surveillance. With regard to this it becomes even more important to provide online services that protect the privacy of their users and avoid censorship by single, powerful entities. To reach these goals, a trusted third party should be avoided. A prototype service which fulfills these goals is DPS-Discuss, a decentralized, pseudonymous online discussion application. It uses the libraries BitNym and Peer-Tor-Peer for pseudonym management and anonymous communication.
2018-04-02
Elgzil, A., Chow, C. E., Aljaedi, A., Alamri, N..  2017.  Cyber Anonymity Based on Software-Defined Networking and Onion Routing (SOR). 2017 IEEE Conference on Dependable and Secure Computing. :358–365.

Cyber anonymity tools have attracted wide attention in resisting network traffic censorship and surveillance, and have played a crucial role for open communications over the Internet. The Onion Routing (Tor) is considered the prevailing technique for circumventing the traffic surveillance and providing cyber anonymity. Tor operates by tunneling a traffic through a series of relays, making such traffic to appear as if it originated from the last relay in the traffic path, rather than from the original user. However, Tor faced some obstructions in carrying out its goal effectively, such as insufficient performance and limited capacity. This paper presents a cyber anonymity technique based on software-defined networking; named SOR, which builds onion-routed tunnels across multiple anonymity service providers. SOR architecture enables any cloud tenants to participate in the anonymity service via software-defined networking. Our proposed architecture leverages the large capacity and robust connectivity of the commercial cloud networks to elevate the performance of the cyber anonymity service.

2017-11-03
Iliou, C., Kalpakis, G., Tsikrika, T., Vrochidis, S., Kompatsiaris, I..  2016.  Hybrid Focused Crawling for Homemade Explosives Discovery on Surface and Dark Web. 2016 11th International Conference on Availability, Reliability and Security (ARES). :229–234.
This work proposes a generic focused crawling framework for discovering resources on any given topic that reside on the Surface or the Dark Web. The proposed crawler is able to seamlessly traverse the Surface Web and several darknets present in the Dark Web (i.e. Tor, I2P and Freenet) during a single crawl by automatically adapting its crawling behavior and its classifier-guided hyperlink selection strategy based on the network type. This hybrid focused crawler is demonstrated for the discovery of Web resources containing recipes for producing homemade explosives. The evaluation experiments indicate the effectiveness of the proposed ap-proach both for the Surface and the Dark Web.
Baravalle, A., Lopez, M. S., Lee, S. W..  2016.  Mining the Dark Web: Drugs and Fake Ids. 2016 IEEE 16th International Conference on Data Mining Workshops (ICDMW). :350–356.
In the last years, governmental bodies have been futilely trying to fight against dark web marketplaces. Shortly after the closing of "The Silk Road" by the FBI and Europol in 2013, new successors have been established. Through the combination of cryptocurrencies and nonstandard communication protocols and tools, agents can anonymously trade in a marketplace for illegal items without leaving any record. This paper presents a research carried out to gain insights on the products and services sold within one of the larger marketplaces for drugs, fake ids and weapons on the Internet, Agora. Our work sheds a light on the nature of the market, there is a clear preponderance of drugs, which accounts for nearly 80% of the total items on sale. The ready availability of counterfeit documents, while they make up for a much smaller percentage of the market, raises worries. Finally, the role of organized crime within Agora is discussed and presented.
Upadhyaya, R., Jain, A..  2016.  Cyber ethics and cyber crime: A deep dwelved study into legality, ransomware, underground web and bitcoin wallet. 2016 International Conference on Computing, Communication and Automation (ICCCA). :143–148.

Future wars will be cyber wars and the attacks will be a sturdy amalgamation of cryptography along with malware to distort information systems and its security. The explosive Internet growth facilitates cyber-attacks. Web threats include risks, that of loss of confidential data and erosion of consumer confidence in e-commerce. The emergence of cyber hack jacking threat in the new form in cyberspace is known as ransomware or crypto virus. The locker bot waits for specific triggering events, to become active. It blocks the task manager, command prompt and other cardinal executable files, a thread checks for their existence every few milliseconds, killing them if present. Imposing serious threats to the digital generation, ransomware pawns the Internet users by hijacking their system and encrypting entire system utility files and folders, and then demanding ransom in exchange for the decryption key it provides for release of the encrypted resources to its original form. We present in this research, the anatomical study of a ransomware family that recently picked up quite a rage and is called CTB locker, and go on to the hard money it makes per user, and its source C&C server, which lies with the Internet's greatest incognito mode-The Dark Net. Cryptolocker Ransomware or the CTB Locker makes a Bitcoin wallet per victim and payment mode is in the form of digital bitcoins which utilizes the anonymity network or Tor gateway. CTB Locker is the deadliest malware the world ever encountered.

2017-08-22
Lazarenko, Aleksandr, Avdoshin, Sergey.  2016.  Anonymity of Tor: Myth and Reality. Proceedings of the 12th Central and Eastern European Software Engineering Conference in Russia. :10:1–10:5.

Privacy enhancing technologies (PETs) are ubiquitous nowadays. They are beneficial for a wide range of users. However, PETs are not always used for legal activity. The present paper is focused on Tor users deanonimization1 using out-of-the box technologies and a basic machine learning algorithm. The aim of the work is to show that it is possible to deanonimize a small fraction of users without having a lot of resources and state-of-the-art machine learning techniques. The deanonimization is a very important task from the point of view of national security. To address this issue, we are using a website fingerprinting attack.

Jansen, Rob, Johnson, Aaron.  2016.  Safely Measuring Tor. Proceedings of the 2016 ACM SIGSAC Conference on Computer and Communications Security. :1553–1567.

Tor is a popular network for anonymous communication. The usage and operation of Tor is not well-understood, however, because its privacy goals make common measurement approaches ineffective or risky. We present PrivCount, a system for measuring the Tor network designed with user privacy as a primary goal. PrivCount securely aggregates measurements across Tor relays and over time to produce differentially private outputs. PrivCount improves on prior approaches by enabling flexible exploration of many diverse kinds of Tor measurements while maintaining accuracy and privacy for each. We use PrivCount to perform a measurement study of Tor of sufficient breadth and depth to inform accurate models of Tor users and traffic. Our results indicate that Tor has 710,000 users connected but only 550,000 active at a given time, that Web traffic now constitutes 91% of data bytes on Tor, and that the strictness of relays' connection policies significantly affects the type of application data they forward.

2017-04-20
Rohrmann, R., Patton, M. W., Chen, H..  2016.  Anonymous port scanning: Performing network reconnaissance through Tor. 2016 IEEE Conference on Intelligence and Security Informatics (ISI). :217–217.

The anonymizing network Tor is examined as one method of anonymizing port scanning tools and avoiding identification and retaliation. Performing anonymized port scans through Tor is possible using Nmap, but parallelization of the scanning processes is required to accelerate the scan rate.