Visible to the public Biblio

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2020-08-07
Mehta, Brijesh B., Gupta, Ruchika, Rao, Udai Pratap, Muthiyan, Mukesh.  2019.  A Scalable (\$\textbackslashtextbackslashalpha, k\$)-Anonymization Approach using MapReduce for Privacy Preserving Big Data Publishing. 2019 10th International Conference on Computing, Communication and Networking Technologies (ICCCNT). :1—6.
Different tools and sources are used to collect big data, which may create privacy issues. k-anonymity, l-diversity, t-closeness etc. privacy preserving data publishing approaches are used data de-identification, but as multiple sources is used to collect the data, chance of re-identification is very high. Anonymization large data is not a trivial task, hence, privacy preserving approaches scalability has become a challenging research area. Researchers explore it by proposing algorithms for scalable anonymization. We further found that in some scenarios efficient anonymization is not enough, timely anonymization is also required. Hence, to incorporate the velocity of data with Scalable k-Anonymization (SKA) approach, we propose a novel approach, Scalable ( α, k)-Anonymization (SAKA). Our proposed approach outperforms in terms of information loss and running time as compared to existing approaches. With best of our knowledge, this is the first proposed scalable anonymization approach for the velocity of data.
2020-07-24
Porwal, Shardha, Mittal, Sangeeta.  2019.  A Flexible Secure Key Delegation Mechanism for CP-ABE with Hidden Access Structure. 2019 11th International Conference on Information Technology and Electrical Engineering (ICITEE). :1—6.

Ciphertext Policy Attribute Based Encryption techniques provide fine grained access control to securely share the data in the organizations where access rights of users vary according to their roles. We have noticed that various key delegation mechanisms are provided for CP-ABE schemes but no key delegation mechanism exists for CP-ABE with hidden access policy. In practical, users' identity may be revealed from access policy in the organizations and unlimited further delegations may results in unauthorized data access. For maintaining the users' anonymity, the access structure should be hidden and every user must be restricted for specified further delegations. In this work, we have presented a flexible secure key delegation mechanism for CP-ABE with hidden access structure. The proposed scheme enhances the capability of existing CP-ABE schemes by supporting flexible delegation, attribute revocation and user revocation with negligible enhancement in computational cost.

2020-07-10
Mi, Xianghang, Feng, Xuan, Liao, Xiaojing, Liu, Baojun, Wang, XiaoFeng, Qian, Feng, Li, Zhou, Alrwais, Sumayah, Sun, Limin, Liu, Ying.  2019.  Resident Evil: Understanding Residential IP Proxy as a Dark Service. 2019 IEEE Symposium on Security and Privacy (SP). :1185—1201.

An emerging Internet business is residential proxy (RESIP) as a service, in which a provider utilizes the hosts within residential networks (in contrast to those running in a datacenter) to relay their customers' traffic, in an attempt to avoid server- side blocking and detection. With the prominent roles the services could play in the underground business world, little has been done to understand whether they are indeed involved in Cybercrimes and how they operate, due to the challenges in identifying their RESIPs, not to mention any in-depth analysis on them. In this paper, we report the first study on RESIPs, which sheds light on the behaviors and the ecosystem of these elusive gray services. Our research employed an infiltration framework, including our clients for RESIP services and the servers they visited, to detect 6 million RESIP IPs across 230+ countries and 52K+ ISPs. The observed addresses were analyzed and the hosts behind them were further fingerprinted using a new profiling system. Our effort led to several surprising findings about the RESIP services unknown before. Surprisingly, despite the providers' claim that the proxy hosts are willingly joined, many proxies run on likely compromised hosts including IoT devices. Through cross-matching the hosts we discovered and labeled PUP (potentially unwanted programs) logs provided by a leading IT company, we uncovered various illicit operations RESIP hosts performed, including illegal promotion, Fast fluxing, phishing, malware hosting, and others. We also reverse engi- neered RESIP services' internal infrastructures, uncovered their potential rebranding and reselling behaviors. Our research takes the first step toward understanding this new Internet service, contributing to the effective control of their security risks.

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.

2020-06-19
Lai, Chengzhe, Du, Yangyang, Men, Jiawei, Zheng, Dong.  2019.  A Trust-based Real-time Map Updating Scheme. 2019 IEEE/CIC International Conference on Communications in China (ICCC). :334—339.

The real-time map updating enables vehicles to obtain accurate and timely traffic information. Especially for driverless cars, real-time map updating can provide high-precision map service to assist the navigation, which requires vehicles to actively upload the latest road conditions. However, due to the untrusted network environment, it is difficult for the real-time map updating server to evaluate the authenticity of the road information from the vehicles. In order to prevent malicious vehicles from deliberately spreading false information and protect the privacy of vehicles from tracking attacks, this paper proposes a trust-based real-time map updating scheme. In this scheme, the public key is used as the identifier of the vehicle for anonymous communication with conditional anonymity. In addition, the blockchain is applied to provide the existence proof for the public key certificate of the vehicle. At the same time, to avoid the spread of false messages, a trust evaluation algorithm is designed. The fog node can validate the received massages from vehicles using Bayesian Inference Model. Based on the verification results, the road condition information is sent to the real-time map updating server so that the server can update the map in time and prevent the secondary traffic accident. In order to calculate the trust value offset for the vehicle, the fog node generates a rating for each message source vehicle, and finally adds the relevant data to the blockchain. According to the result of security analysis, this scheme can guarantee the anonymity and prevent the Sybil attack. Simulation results show that the proposed scheme is effective and accurate in terms of real-time map updating and trust values calculating.

2020-05-29
Liu, Xuejie, Bing, Qi, Lu, Xinhua, Zhong, Lihong, Wei, Da, Qu, Guannan.  2019.  An Identity Privacy Protection Strategy in Vehicle Named Data Network. 2019 IEEE International Conferences on Ubiquitous Computing Communications (IUCC) and Data Science and Computational Intelligence (DSCI) and Smart Computing, Networking and Services (SmartCNS). :818—822.

Although Vehicle Named Data Network (VNDN) possess the communication benefits of Named Data Network and Vehicle Opportunity Network, it also introduces some new privacy problems, including the identity security of Data Requesters and Data Providers. Data providers in VNDN need to sign data packets directly, which will leak the identity information of the providers, while the vicinity malicious nodes can access the sensitive information of Data Requesters by analyzing the relationship between Data Requesters and the data names in Interest Packages that are sent directly in plaintext. In order to solve the above privacy problems, this paper presents an identity privacy protection strategy for Data Requesters and Data Providers in VNDN. A ring signature scheme is used to hide the correlation between the signature and the data provider and the anonymous proxy idea is used to protect the real identity of the data requester in the proposed strategy. Security Analysis and experiments in the ONE-based VNDN platform indicate that the proposed strategy is effective and practical.

2020-01-20
Rasheed, Amar, Hashemi, Ray R., Bagabas, Ayman, Young, Jeffrey, Badri, Chanukya, Patel, Keyur.  2019.  Configurable Anonymous Authentication Schemes For The Internet of Things (IoT). 2019 IEEE International Conference on RFID (RFID). :1–8.
The Internet of Things (IoT) has revolutionized the way of how pervasive computing devices communicate and disseminate information over the global network. A plethora of user data is collected and logged daily into cloud-based servers. Such data can be analyzed by the IoT infrastructure to capture users' behaviors (e.g. users' location, tagging of smart home occupancy). This brings a new set of security challenges, specifically user anonymity. Existing access control and authentication technologies failed to support user anonymity. They relied on the surrendering of the device/user authentication parameters to the trusted server, which hence could be utilized by the IoT infrastructure to track users' behavioral patterns. This paper, presents two novel configurable privacy-preserving authentication schemes. User anonymity capabilities were incorporated into our proposed authentication schemes through the implementation of two crypto-based approaches (i) Zero Knowledge Proof (ZKP) and (ii) Verifiable Common Secret Encoding (VCSE). We consider a user-oriented approach when determining user anonymity. The proposed authentication schemes are dynamically capable of supporting various levels of user privacy based on the user preferences. To validate the two schemes, they were fully implemented and deployed on an IoT testbed. We have tested the performance of each proposed schemes in terms of power consumption and computation time. Based on our performance evaluation results, the proposed ZKP-based approach provides better performance compared to the VCSE-based approach.
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.

2019-11-04
Abani, Noor, Braun, Torsten, Gerla, Mario.  2018.  Betweenness Centrality and Cache Privacy in Information-Centric Networks. Proceedings of the 5th ACM Conference on Information-Centric Networking. :106-116.

In-network caching is a feature shared by all proposed Information Centric Networking (ICN) architectures as it is critical to achieving a more efficient retrieval of content. However, the default "cache everything everywhere" universal caching scheme has caused the emergence of several privacy threats. Timing attacks are one such privacy breach where attackers can probe caches and use timing analysis of data retrievals to identify if content was retrieved from the data source or from the cache, the latter case inferring that this content was requested recently. We have previously proposed a betweenness centrality based caching strategy to mitigate such attacks by increasing user anonymity. We demonstrated its efficacy in a transit-stub topology. In this paper, we further investigate the effect of betweenness centrality based caching on cache privacy and user anonymity in more general synthetic and real world Internet topologies. It was also shown that an attacker with access to multiple compromised routers can locate and track a mobile user by carrying out multiple timing analysis attacks from various parts of the network. We extend our privacy evaluation to a scenario with mobile users and show that a betweenness centrality based caching policy provides a mobile user with path privacy by increasing an attacker's difficulty in locating a moving user or identifying his/her route.

2019-08-05
Kita, Kentaro, Kurihara, Yoshiki, Koizumi, Yuki, Hasegawa, Toru.  2018.  Location Privacy Protection with a Semi-honest Anonymizer in Information Centric Networking. Proceedings of the 5th ACM Conference on Information-Centric Networking. :95–105.
Location-based services, which provide services based on locations of consumers' interests, are becoming essential for our daily lives. Since the location of a consumer's interest contains private information, several studies propose location privacy protection mechanisms using an anonymizer, which sends queries specifying anonymous location sets, each of which contains k - 1 locations in addition to a location of a consumer's interest, to an LBS provider based on the k-anonymity principle. The anonymizer is, however, assumed to be trusted/honest, and hence it is a single point of failure in terms of privacy leakage. To address this privacy issue, this paper designs a semi-honest anonymizer to protect location privacy in NDN networks. This study first reveals that session anonymity and location anonymity must be achieved to protect location privacy with a semi-honest anonymizer. Session anonymity is to hide who specifies which anonymous location set and location anonymity is to hide a location of a consumer's interest in a crowd of locations. We next design an architecture to achieve session anonymity and an algorithm to generate anonymous location sets achieving location anonymity. Our evaluations show that the architecture incurs marginal overhead to achieve session anonymity and anonymous location sets generated by the algorithm sufficiently achieve location anonymity.
2019-03-18
Tran, Muoi, Luu, Loi, Kang, Min Suk, Bentov, Iddo, Saxena, Prateek.  2018.  Obscuro: A Bitcoin Mixer Using Trusted Execution Environments. Proceedings of the 34th Annual Computer Security Applications Conference. :692–701.
Bitcoin provides only pseudo-anonymous transactions, which can be exploited to link payers and payees – defeating the goal of anonymous payments. To thwart such attacks, several Bitcoin mixers have been proposed, with the objective of providing unlinkability between payers and payees. However, existing Bitcoin mixers can be regarded as either insecure or inefficient. We present Obscuro, a highly efficient and secure Bitcoin mixer that utilizes trusted execution environments (TEEs). With the TEE's confidentiality and integrity guarantees for code and data, our mixer design ensures the correct mixing operations and the protection of sensitive data (i.e., private keys and mixing logs), ruling out coin theft and address linking attacks by a malicious service provider. Yet, the TEE-based implementation does not prevent the manipulation of inputs (e.g., deposit submissions, blockchain feeds) to the mixer, hence Obscuro is designed to overcome such limitations: it (1) offers an indirect deposit mechanism to prevent a malicious service provider from rejecting benign user deposits; and (2) scrutinizes blockchain feeds to prevent deposits from being mixed more than once (thus degrading anonymity) while being eclipsed from the main blockchain branch. In addition, Obscuro provides several unique anonymity features (e.g., minimum mixing set size guarantee, resistant to dropping user deposits) that are not available in existing centralized and decentralized mixers. Our prototype of Obscuro is built using Intel SGX and we demonstrate its effectiveness in Bitcoin Testnet. Our implementation mixes 1000 inputs in just 6.49 seconds, which vastly outperforms all of the existing decentralized mixers.
2019-03-04
Aborisade, O., Anwar, M..  2018.  Classification for Authorship of Tweets by Comparing Logistic Regression and Naive Bayes Classifiers. 2018 IEEE International Conference on Information Reuse and Integration (IRI). :269–276.

At a time when all it takes to open a Twitter account is a mobile phone, the act of authenticating information encountered on social media becomes very complex, especially when we lack measures to verify digital identities in the first place. Because the platform supports anonymity, fake news generated by dubious sources have been observed to travel much faster and farther than real news. Hence, we need valid measures to identify authors of misinformation to avert these consequences. Researchers propose different authorship attribution techniques to approach this kind of problem. However, because tweets are made up of only 280 characters, finding a suitable authorship attribution technique is a challenge. This research aims to classify authors of tweets by comparing machine learning methods like logistic regression and naive Bayes. The processes of this application are fetching of tweets, pre-processing, feature extraction, and developing a machine learning model for classification. This paper illustrates the text classification for authorship process using machine learning techniques. In total, there were 46,895 tweets used as both training and testing data, and unique features specific to Twitter were extracted. Several steps were done in the pre-processing phase, including removal of short texts, removal of stop-words and punctuations, tokenizing and stemming of texts as well. This approach transforms the pre-processed data into a set of feature vector in Python. Logistic regression and naive Bayes algorithms were applied to the set of feature vectors for the training and testing of the classifier. The logistic regression based classifier gave the highest accuracy of 91.1% compared to the naive Bayes classifier with 89.8%.

2019-01-31
Kazemi, M., Delavar, M., Mohajeri, J., Salmasizadeh, M..  2018.  On the Security of an Efficient Anonymous Authentication with Conditional Privacy-Preserving Scheme for Vehicular Ad Hoc Networks. Iranian Conference on Electrical Engineering (ICEE). :510–514.

Design of anonymous authentication scheme is one of the most important challenges in Vehicular Ad hoc Networks (VANET). Most of the existing schemes have high computational and communication overhead and they do not meet security requirements. Recently, Azees et al. have introduced an Efficient Anonymous Authentication with Conditional Privacy-Preserving (EAAP) scheme for VANET and claimed that it is secure. In this paper, we show that this protocol is vulnerable against replay attack, impersonation attack and message modification attack. Also, we show that the messages sent by a vehicle are linkable. Therefore, an adversary can easily track the vehicles. In addition, it is shown that vehicles face with some problems when they enter in a new Trusted Authority (TA) range. As a solution, we propose a new authentication protocol which is more secure than EAAP protocol without increasing its computational and communication overhead.

Wang, Ningfei, Ji, Shouling, Wang, Ting.  2018.  Integration of Static and Dynamic Code Stylometry Analysis for Programmer De-Anonymization. Proceedings of the 11th ACM Workshop on Artificial Intelligence and Security. :74–84.

De-anonymizing the authors of anonymous code (i.e., code stylometry) entails significant privacy and security implications. Most existing code stylometry methods solely rely on static (e.g., lexical, layout, and syntactic) features extracted from source code, while neglecting its key difference from regular text – it is executable! In this paper, we present Sundae, a novel code de-anonymization framework that integrates both static and dynamic stylometry analysis. Compared with the existing solutions, Sundae departs in significant ways: (i) it requires much less number of static, hand-crafted features; (ii) it requires much less labeled data for training; and (iii) it can be readily extended to new programmers once their stylometry information becomes available Through extensive evaluation on benchmark datasets, we demonstrate that Sundae delivers strong empirical performance. For example, under the setting of 229 programmers and 9 problems, it outperforms the state-of-art method by a margin of 45.65% on Python code de-anonymization. The empirical results highlight the integration of static and dynamic analysis as a promising direction for code stylometry research.

Eskeland, Sigurd.  2018.  Temporal Anonymity in the AMS Scenario Without a TTP. Proceedings of the 12th European Conference on Software Architecture: Companion Proceedings. :57:1–57:7.

Smart meters provide fine-grained electricity consumption reporting to electricity providers. This constitutes an invasive factor into the privacy of the consumers, which has raised many privacy concerns. Although billing requires attributable consumption reporting, consumption reporting for operational monitoring and control measures can be non-attributable. However, the privacy-preserving AMS schemes in the literature tend to address these two categories disjointly — possibly due to their somewhat contradictory characteristics. In this paper, we propose an efficient two-party privacy-preserving cryptographic scheme that addresses operational control measures and billing jointly. It is computationally efficient as it is based on symmetric cryptographic primitives. No online trusted third party (TTP) is required.

Mohammady, Meisam, Wang, Lingyu, Hong, Yuan, Louafi, Habib, Pourzandi, Makan, Debbabi, Mourad.  2018.  Preserving Both Privacy and Utility in Network Trace Anonymization. Proceedings of the 2018 ACM SIGSAC Conference on Computer and Communications Security. :459–474.

As network security monitoring grows more sophisticated, there is an increasing need for outsourcing such tasks to third-party analysts. However, organizations are usually reluctant to share their network traces due to privacy concerns over sensitive information, e.g., network and system configuration, which may potentially be exploited for attacks. In cases where data owners are convinced to share their network traces, the data are typically subjected to certain anonymization techniques, e.g., CryptoPAn, which replaces real IP addresses with prefix-preserving pseudonyms. However, most such techniques either are vulnerable to adversaries with prior knowledge about some network flows in the traces, or require heavy data sanitization or perturbation, both of which may result in a significant loss of data utility. In this paper, we aim to preserve both privacy and utility through shifting the trade-off from between privacy and utility to between privacy and computational cost. The key idea is for the analysts to generate and analyze multiple anonymized views of the original network traces; those views are designed to be sufficiently indistinguishable even to adversaries armed with prior knowledge, which preserves the privacy, whereas one of the views will yield true analysis results privately retrieved by the data owner, which preserves the utility. We formally analyze the privacy of our solution and experimentally evaluate it using real network traces provided by a major ISP. The results show that our approach can significantly reduce the level of information leakage (e.g., less than 1% of the information leaked by CryptoPAn) with comparable utility.

Rahman, Mizanur, Hernandez, Nestor, Carbunar, Bogdan, Chau, Duen Horng.  2018.  Search Rank Fraud De-Anonymization in Online Systems. Proceedings of the 29th on Hypertext and Social Media. :174–182.

We introduce the fraud de-anonymization problem, that goes beyond fraud detection, to unmask the human masterminds responsible for posting search rank fraud in online systems. We collect and study search rank fraud data from Upwork, and survey the capabilities and behaviors of 58 search rank fraudsters recruited from 6 crowdsourcing sites. We propose Dolos, a fraud de-anonymization system that leverages traits and behaviors extracted from these studies, to attribute detected fraud to crowdsourcing site fraudsters, thus to real identities and bank accounts. We introduce MCDense, a min-cut dense component detection algorithm to uncover groups of user accounts controlled by different fraudsters, and leverage stylometry and deep learning to attribute them to crowdsourcing site profiles. Dolos correctly identified the owners of 95% of fraudster-controlled communities, and uncovered fraudsters who promoted as many as 97.5% of fraud apps we collected from Google Play. When evaluated on 13,087 apps (820,760 reviews), which we monitored over more than 6 months, Dolos identified 1,056 apps with suspicious reviewer groups. We report orthogonal evidence of their fraud, including fraud duplicates and fraud re-posts.

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.

Tewari, A., Gupta, B. B..  2018.  A Robust Anonymity Preserving Authentication Protocol for IoT Devices. 2018 IEEE International Conference on Consumer Electronics (ICCE). :1–5.

In spite of being a promising technology which will make our lives a lot easier we cannot be oblivious to the fact IoT is not safe from online threat and attacks. Thus, along with the growth of IoT we also need to work on its aspects. Taking into account the limited resources that these devices have it is important that the security mechanisms should also be less complex and do not hinder the actual functionality of the device. In this paper, we propose an ECC based lightweight authentication for IoT devices which deploy RFID tags at the physical layer. ECC is a very efficient public key cryptography mechanism as it provides privacy and security with lesser computation overhead. We also present a security and performance analysis to verify the strength of our proposed approach.

Nakamura, T., Nishi, H..  2018.  TMk-Anonymity: Perturbation-Based Data Anonymization Method for Improving Effectiveness of Secondary Use. IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society. :3138–3143.

The recent emergence of smartphones, cloud computing, and the Internet of Things has brought about the explosion of data creation. By collating and merging these enormous data with other information, services that use information become more sophisticated and advanced. However, at the same time, the consideration of privacy violations caused by such merging is indispensable. Various anonymization methods have been proposed to preserve privacy. The conventional perturbation-based anonymization method of location data adds comparatively larger noise, and the larger noise makes it difficult to utilize the data effectively for secondary use. In this research, to solve these problems, we first clarified the definition of privacy preservation and then propose TMk-anonymity according to the definition.

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.

Chen, Y., Wu, B..  2018.  An Efficient Algorithm for Minimal Edit Cost of Graph Degree Anonymity. 2018 IEEE International Conference on Applied System Invention (ICASI). :574–577.

Personal privacy is an important issue when publishing social network data. An attacker may have information to reidentify private data. So, many researchers developed anonymization techniques, such as k-anonymity, k-isomorphism, l-diversity, etc. In this paper, we focus on graph k-degree anonymity by editing edges. Our method is divided into two steps. First, we propose an efficient algorithm to find a new degree sequence with theoretically minimal edit cost. Second, we insert and delete edges based on the new degree sequence to achieve k-degree anonymity.

Das, D., Meiser, S., Mohammadi, E., Kate, A..  2018.  Anonymity Trilemma: Strong Anonymity, Low Bandwidth Overhead, Low Latency - Choose Two. 2018 IEEE Symposium on Security and Privacy (SP). :108–126.

This work investigates the fundamental constraints of anonymous communication (AC) protocols. We analyze the relationship between bandwidth overhead, latency overhead, and sender anonymity or recipient anonymity against the global passive (network-level) adversary. We confirm the trilemma that an AC protocol can only achieve two out of the following three properties: strong anonymity (i.e., anonymity up to a negligible chance), low bandwidth overhead, and low latency overhead. We further study anonymity against a stronger global passive adversary that can additionally passively compromise some of the AC protocol nodes. For a given number of compromised nodes, we derive necessary constraints between bandwidth and latency overhead whose violation make it impossible for an AC protocol to achieve strong anonymity. We analyze prominent AC protocols from the literature and depict to which extent those satisfy our necessary constraints. Our fundamental necessary constraints offer a guideline not only for improving existing AC systems but also for designing novel AC protocols with non-traditional bandwidth and latency overhead choices.

2019-01-16
Gulyas, Gabor Gyorgy, Some, Dolière Francis, Bielova, Nataliia, Castelluccia, Claude.  2018.  To Extend or Not to Extend: On the Uniqueness of Browser Extensions and Web Logins. Proceedings of the 2018 Workshop on Privacy in the Electronic Society. :14–27.
Recent works showed that websites can detect browser extensions that users install and websites they are logged into. This poses significant privacy risks, since extensions and Web logins that reflect user's behavior, can be used to uniquely identify users on the Web. This paper reports on the first large-scale behavioral uniqueness study based on 16,393 users who visited our website. We test and detect the presence of 16,743 Chrome extensions, covering 28% of all free Chrome extensions. We also detect whether the user is connected to 60 different websites. We analyze how unique users are based on their behavior, and find out that 54.86% of users that have installed at least one detectable extension are unique; 19.53% of users are unique among those who have logged into one or more detectable websites; and 89.23% are unique among users with at least one extension and one login. We use an advanced fingerprinting algorithm and show that it is possible to identify a user in less than 625 milliseconds by selecting the most unique combinations of extensions. Because privacy extensions contribute to the uniqueness of users, we study the trade-off between the amount of trackers blocked by such extensions and how unique the users of these extensions are. We have found that privacy extensions should be considered more useful than harmful. The paper concludes with possible countermeasures.
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%).