arXiv subjects

Gene Tsudik

Publications and source records attributed to Gene Tsudik.

71 records · Page 4Linked to original sources

arXiv2015

To NACK or not to NACK? Negative Acknowledgments in Information-Centric Networking

Information-Centric Networking (ICN) is an internetworking paradigm that offers an alternative to the current IP\nobreakdash-based Internet architecture. ICN's most distinguishing feature is its emphasis on information (content) instead of communication endpoints. One important open issue in ICN is whether negative acknowledgments (NACKs) at the network layer are useful for notifying downstream nodes about forwarding failures, or requests for incorrect or non-existent information. In benign settings, NACKs are beneficial for ICN architectures, such as CCNx and NDN, since they flush state in routers and notify consumers. In terms of security, NACKs seem useful as they can help mitigating so-called Interest Flooding attacks. However, as we show in this paper, network-layer NACKs also have some unpleasant security implications. We consider several types of NACKs and discuss their security design requirements and implications. We also demonstrate that providing secure NACKs triggers the threat of producer-bound flooding attacks. Although we discuss some potential countermeasures to these attacks, the main conclusion of this paper is that network-layer NACKs are best avoided, at least for security reasons.

cs.NI↗

arXiv2015

The Chills and Thrills of Whole Genome Sequencing

In recent years, Whole Genome Sequencing (WGS) evolved from a futuristic-sounding research project to an increasingly affordable technology for determining complete genome sequences of complex organisms, including humans. This prompts a wide range of revolutionary applications, as WGS promises to improve modern healthcare and provide a better understanding of the human genome -- in particular, its relation to diseases and response to treatments. However, this progress raises worrisome privacy and ethical issues, since, besides uniquely identifying its owner, the genome contains a treasure trove of highly personal and sensitive information. In this article, after summarizing recent advances in genomics, we discuss some important privacy issues associated with human genomic information and identify a number of particularly relevant research challenges.

cs.CR↗

arXiv2014

Elements of Trust in Named-Data Networking

In contrast to today's IP-based host-oriented Internet architecture, Information-Centric Networking (ICN) emphasizes content by making it directly addressable and routable. Named Data Networking (NDN) architecture is an instance of ICN that is being developed as a candidate next-generation Internet architecture. By opportunistically caching content within the network (in routers), NDN appears to be well-suited for large-scale content distribution and for meeting the needs of increasingly mobile and bandwidth-hungry applications that dominate today's Internet. One key feature of NDN is the requirement for each content object to be digitally signed by its producer. Thus, NDN should be, in principle, immune to distributing fake (aka "poisoned") content. However, in practice, this poses two challenges for detecting fake content in NDN routers: (1) overhead due to signature verification and certificate chain traversal, and (2) lack of trust context, i.e., determining which public keys are trusted to verify which content. Because of these issues, NDN does not force routers to verify content signatures, which makes the architecture susceptible to content poisoning attacks. This paper explores root causes of, and some cures for, content poisoning attacks in NDN. In the process, it becomes apparent that meaningful mitigation of content poisoning is contingent upon a network-layer trust management architecture, elements of which we construct while carefully justifying specific design choices. This work represents the initial effort towards comprehensive trust management for NDN.

cs.NI↗

arXiv2014

Are 140 Characters Enough? A Large-Scale Linkability Study of Tweets

Microblogging is a very popular Internet activity that informs and entertains great multitudes of people world-wide via quickly and scalably disseminated terse messages containing all kinds of newsworthy utterances. Even though microblogging is neither designed nor meant to emphasize privacy, numerous contributors hide behind pseudonyms and compartmentalize their different incarnations via multiple accounts within the same, or across multiple, site(s). Prior work has shown that stylometric analysis is a very powerful tool capable of linking product or service reviews and blogs that are produced by the same author when the number of authors is large. In this paper, we explore linkability of tweets. Our results, based on a very large corpus of tweets, clearly demonstrate that, at least for relatively active tweeters, linkability of tweets by the same author is easily attained even when the number of tweeters is large. We also show that our linkability results hold for a set of actual Twitter users who tweet from multiple accounts. This has some obvious privacy implications, both positive and negative.

cs.IR↗

arXiv2014

Fighting Authorship Linkability with Crowdsourcing

Massive amounts of contributed content -- including traditional literature, blogs, music, videos, reviews and tweets -- are available on the Internet today, with authors numbering in many millions. Textual information, such as product or service reviews, is an important and increasingly popular type of content that is being used as a foundation of many trendy community-based reviewing sites, such as TripAdvisor and Yelp. Some recent results have shown that, due partly to their specialized/topical nature, sets of reviews authored by the same person are readily linkable based on simple stylometric features. In practice, this means that individuals who author more than a few reviews under different accounts (whether within one site or across multiple sites) can be linked, which represents a significant loss of privacy. In this paper, we start by showing that the problem is actually worse than previously believed. We then explore ways to mitigate authorship linkability in community-based reviewing. We first attempt to harness the global power of crowdsourcing by engaging random strangers into the process of re-writing reviews. As our empirical results (obtained from Amazon Mechanical Turk) clearly demonstrate, crowdsourcing yields impressively sensible reviews that reflect sufficiently different stylometric characteristics such that prior stylometric linkability techniques become largely ineffective. We also consider using machine translation to automatically re-write reviews. Contrary to what was previously believed, our results show that translation decreases authorship linkability as the number of intermediate languages grows. Finally, we explore the combination of crowdsourcing and machine translation and report on the results.

cs.DL↗

arXiv2013

Covert Ephemeral Communication in Named Data Networking

In the last decade, there has been a growing realization that the current Internet Protocol is reaching the limits of its senescence. This has prompted several research efforts that aim to design potential next-generation Internet architectures. Named Data Networking (NDN), an instantiation of the content-centric approach to networking, is one such effort. In contrast with IP, NDN routers maintain a significant amount of user-driven state. In this paper we investigate how to use this state for covert ephemeral communication (CEC). CEC allows two or more parties to covertly exchange ephemeral messages, i.e., messages that become unavailable after a certain amount of time. Our techniques rely only on network-layer, rather than application-layer, services. This makes our protocols robust, and communication difficult to uncover. We show that users can build high-bandwidth CECs exploiting features unique to NDN: in-network caches, routers' forwarding state and name matching rules. We assess feasibility and performance of proposed cover channels using a local setup and the official NDN testbed.

cs.CR↗

arXiv2013

Poseidon: Mitigating Interest Flooding DDoS Attacks in Named Data Networking

Content-Centric Networking (CCN) is an emerging networking paradigm being considered as a possible replacement for the current IP-based host-centric Internet infrastructure. In CCN, named content becomes a first-class entity. CCN focuses on content distribution, which dominates current Internet traffic and is arguably not well served by IP. Named-Data Networking (NDN) is an example of CCN. NDN is also an active research project under the NSF Future Internet Architectures (FIA) program. FIA emphasizes security and privacy from the outset and by design. To be a viable Internet architecture, NDN must be resilient against current and emerging threats. This paper focuses on distributed denial-of-service (DDoS) attacks; in particular we address interest flooding, an attack that exploits key architectural features of NDN. We show that an adversary with limited resources can implement such attack, having a significant impact on network performance. We then introduce Poseidon: a framework for detecting and mitigating interest flooding attacks. Finally, we report on results of extensive simulations assessing proposed countermeasure.

cs.NI↗

arXiv2012

DoS and DDoS in Named-Data Networking

With the growing realization that current Internet protocols are reaching the limits of their senescence, a number of on-going research efforts aim to design potential next-generation Internet architectures. Although they vary in maturity and scope, in order to avoid past pitfalls, these efforts seek to treat security and privacy as fundamental requirements. Resilience to Denial-of-Service (DoS) attacks that plague today's Internet is a major issue for any new architecture and deserves full attention. In this paper, we focus on DoS in a specific candidate next-generation Internet architecture called Named-Data Networking (NDN) -- an instantiation of Information-Centric Networking approach. By stressing content dissemination, NDN appears to be attractive and viable approach to many types of current and emerging communication models. It also incorporates some basic security features that mitigate certain attacks. However, NDN's resilience to DoS attacks has not been analyzed to-date. This paper represents the first step towards assessment and possible mitigation of DoS in NDN. After identifying and analyzing several new types of attacks, it investigates their variations, effects and counter-measures. This paper also sheds some light on the long-standing debate about relative virtues of self-certifying, as opposed to human-readable, names.

cs.NI↗

arXiv2012

Securing Instrumented Environments over Content-Centric Networking: the Case of Lighting Control

Instrumented environments, such as modern building automation systems (BAS), are becoming commonplace and are increasingly interconnected with (and sometimes by) enterprise networks and the Internet. Regardless of the underlying communication platform, secure control of devices in such environments is a challenging task. The current trend is to move from proprietary communication media and protocols to IP over Ethernet. While the move to IP represents progress, new and different Internet architectures might be better-suited for instrumented environments. In this paper, we consider security of instrumented environments in the context of Content-Centric Networking (CCN). In particular, we focus on building automation over Named-Data Networking (NDN), a prominent instance of CCN. After identifying security requirements in a specific BAS sub-domain (lighting control), we construct a concrete NDN-based security architecture, analyze its properties and report on preliminary implementation and experimental results. We believe in securing a communication paradigm well outside of its claimed forte of content distribution. At the same time, we provide a viable (secure and efficient) communication platform for a class of instrumented environments exemplified by lighting control.

cs.CR↗

arXiv2012

Optimizing Bi-directional Low-Latency Communication in Named Data Networking

Content-Centric Networking (CCN) is a concept being considered as a potential future alternative to, or replacement for, today's Internet IP-style packet-switched host-centric networking. One factor making CCN attractive is its focus on content distribution, which dominates current Internet traffic and which is arguably not well-served by IP. Named Data Networking (NDN) is a prominent example of CCN. It is also one of several on-going research efforts aiming to design and develop a full-blown candidate future Internet architecture. Although NDN's primary motivation is content distribution, it is envisioned to support other types of traffic, such as conferencing (audio, video) as well as more historical applications, such as remote login. However, it is unclear how suitable NDN is for applications that are not obviously content-centric. In this paper, we explore NDN in the context of a class of applications that involve low- latency bidirectional communication. Specifically, we propose a few architectural amendments to NDN that provide significantly better throughput and lower latency for this class of applications. The proposed approach is validated via both simulations and testbed experiments.

cs.NI↗

arXiv2012

Harvesting SSL Certificate Data to Identify Web-Fraud

Web-fraud is one of the most unpleasant features of today's Internet. Two well-known examples of fraudulent activities on the web are phishing and typosquatting. Their effects range from relatively benign (such as unwanted ads) to downright sinister (especially, when typosquatting is combined with phishing). This paper presents a novel technique to detect web-fraud domains that utilize HTTPS. To this end, we conduct the first comprehensive study of SSL certificates. We analyze certificates of legitimate and popular domains and those used by fraudulent ones. Drawing from extensive measurements, we build a classifier that detects such malicious domains with high accuracy.

cs.CR↗

arXiv2012

Exploring Linkablility of Community Reviewing

Large numbers of people all over the world read and contribute to various review sites. Many contributors are understandably concerned about privacy; specifically, about linkability of reviews (and accounts) across review sites. In this paper, we study linkability of community reviewing and try to answer the question: to what extent are "anonymous" reviews linkable, i.e., likely authored by the same contributor? Based on a very large set of reviews from a popular site (Yelp), we show that a high percentage of ostensibly anonymous reviews can be linked with very high confidence. This is despite the fact that we use very simple models and equally simple features set. Our study suggests that contributors reliably expose their identities in reviews. This has important implications for cross-referencing accounts between different review sites. Also, techniques used in our study could be adopted by review sites to give contributors feedback about privacy of their reviews.

cs.CR↗

arXiv2012

ANDaNA: Anonymous Named Data Networking Application

Content-centric networking -- also known as information-centric networking (ICN) -- shifts emphasis from hosts and interfaces (as in today's Internet) to data. Named data becomes addressable and routable, while locations that currently store that data become irrelevant to applications. Named Data Networking (NDN) is a large collaborative research effort that exemplifies the content-centric approach to networking. NDN has some innate privacy-friendly features, such as lack of source and destination addresses on packets. However, as discussed in this paper, NDN architecture prompts some privacy concerns mainly stemming from the semantic richness of names. We examine privacy-relevant characteristics of NDN and present an initial attempt to achieve communication privacy. Specifically, we design an NDN add-on tool, called ANDaNA, that borrows a number of features from Tor. As we demonstrate via experiments, it provides comparable anonymity with lower relative overhead.

cs.CR↗

arXiv2011

Countering Gattaca: Efficient and Secure Testing of Fully-Sequenced Human Genomes (Full Version)

Recent advances in DNA sequencing technologies have put ubiquitous availability of fully sequenced human genomes within reach. It is no longer hard to imagine the day when everyone will have the means to obtain and store one's own DNA sequence. Widespread and affordable availability of fully sequenced genomes immediately opens up important opportunities in a number of health-related fields. In particular, common genomic applications and tests performed in vitro today will soon be conducted computationally, using digitized genomes. New applications will be developed as genome-enabled medicine becomes increasingly preventive and personalized. However, this progress also prompts significant privacy challenges associated with potential loss, theft, or misuse of genomic data. In this paper, we begin to address genomic privacy by focusing on three important applications: Paternity Tests, Personalized Medicine, and Genetic Compatibility Tests. After carefully analyzing these applications and their privacy requirements, we propose a set of efficient techniques based on private set operations. This allows us to implement in in silico some operations that are currently performed via in vitro methods, in a secure fashion. Experimental results demonstrate that proposed techniques are both feasible and practical today.

cs.CR↗

arXiv2010

GDB: Group Distance Bounding Protocols

Secure distance bounding (DB) protocols allow one entity, the verifier, to securely obtain an upper-bound on the distance to another entity, the prover. Thus far, DB was considered mostly in the context of a single prover and a single verifier. There has been no substantial prior work on secure DB in group settings, where a set of provers interact with a set of verifiers. The need for group distance bounding (GDB) is motivated by many practical scenarios, including: group device pairing, location-based access control and secure distributed localization. GDB is also useful in mission-critical networks and automotive computer systems. This paper addresses, for the first time, GDB protocols by utilizing the new passive DB primitive and the novel mutual multi-party GDB protocol. We show how they can be used to construct secure and efficient GDB protocols for various settings. We analyze security and performance of our protocols and compare them with existing DB techniques when applied to group settings.

cs.CR↗

arXiv2010

Towards Plugging Privacy Leaks in Domain Name System

Privacy leaks are an unfortunate and an integral part of the current Internet domain name resolution. Each DNS query generated by a user reveals -- to one or more DNS servers -- the origin and target of that query. Over time, a user's browsing behavior might be exposed to entities with little or no trust. Current DNS privacy leaks stem from fundamental DNS features and are not easily fixable by simple patches. Moreover, privacy issues have been overlooked by DNS security efforts (i.e. DNSSEC) and are thus likely to propagate into future versions of DNS. In order to mitigate privacy issues in current DNS, this paper proposes a Privacy-Preserving Domain Name System (PPDNS), which maintains privacy during domain name resolution. PPDNS is based on distributed hash tables (DHTs), an alternative naming infrastructure, and computational private information retrieval (cPIR), an advanced cryptographic construct. PPDNS takes advantage of the DHT's index structure to improve name resolution query privacy, while leveraging cPIR to reduce communication overhead for bandwidth-sensitive clients. Our analysis shows that PPDNS is a viable approach for obtaining a higher degree of privacy for name resolution queries. PPDNS also serves as a demonstration of blending advanced systems techniques with their cryptographic counterparts.

cs.CR↗

arXiv2009

Privacy-Preserving Querying in Sensor Networks

Wireless Sensor Networks (WSNs) provide sensing and monitoring services by means of many tiny autonomous devices equipped with wireless radio transceivers. As WSNs are deployed on a large-scale and/or on long-term basis, not only traditional security but also privacy issues must be taken into account. Furthermore, when network operators offer on-demand access to sensor measurements to their clients, query mechanisms should ideally leak neither client interests nor query patterns. In this paper, we present a privacy-preserving WSN query mechanism that uses standard cryptographic techniques. Besides preventing unauthorized entities from accessing sensor readings, it minimizes leakage of (potentially sensitive) information about users' query targets and patterns.

cs.CR↗