Overcoming Adversaries in Sensor Networks: A Survey of Theoretical Models and Algorithmic Approaches for Tolerating Malicious Interference <s> A. The Scope of this Survey <s> This paper describes the concept of sensor networks which has been made viable by the convergence of micro-electro-mechanical systems technology, wireless communications and digital electronics. First, the sensing tasks and the potential sensor networks applications are explored, and a review of factors influencing the design of sensor networks is provided. Then, the communication architecture for sensor networks is outlined, and the algorithms and protocols developed for each layer in the literature are explored. Open research issues for the realization of sensor networks are also discussed. <s> BIB001 </s> Overcoming Adversaries in Sensor Networks: A Survey of Theoretical Models and Algorithmic Approaches for Tolerating Malicious Interference <s> A. The Scope of this Survey <s> Advances in hardware and wireless network technologies have created low-cost, low-power, multifunctional miniature sensor devices. These devices make up hundreds or thousands of ad hoc tiny sensor nodes spread across a geographical area. These sensor nodes collaborate among themselves to establish a sensing network. A sensor network can provide access to information anytime, anywhere by collecting, processing, analyzing and disseminating data. Thus, the network actively participates in creating a smart environment. <s> BIB002 </s> Overcoming Adversaries in Sensor Networks: A Survey of Theoretical Models and Algorithmic Approaches for Tolerating Malicious Interference <s> A. The Scope of this Survey <s> Theorists and practitioners have fairly different perspectives on how wireless broadcast works. Theorists think about synchrony; practitioners think about backoff. Theorists assume reliable communication; practitioners worry about collisions. The examples are endless. Our goal is to begin to reconcile the theory and practice of wireless broadcast, in the presence of failures. We propose new models for wireless broadcast and use them to examine what makes a broadcast model good. In the process, we pose some interesting questions that help to bridge the gap. <s> BIB003 </s> Overcoming Adversaries in Sensor Networks: A Survey of Theoretical Models and Algorithmic Approaches for Tolerating Malicious Interference <s> A. The Scope of this Survey <s> Developing algorithms for sensor networks - and proving their correctness and performance - requires simplifying but still realistic models. This paper surveys various models in use today and puts them into perspective. In addition, we propose interesting models which are not widely adopted by the community so far. <s> BIB004 </s> Overcoming Adversaries in Sensor Networks: A Survey of Theoretical Models and Algorithmic Approaches for Tolerating Malicious Interference <s> A. The Scope of this Survey <s> Wireless sensor networking continues to evolve as one of the most exciting and challenging research areas of our time. Intrinsically, there are many applications of wireless sensor networks that collect and disseminate sensitive and important information. In order for many implementations of these applications to operate successfully, it is necessary to maintain the privacy and security of the transmitted data. What remains undefined, however, is an agreeable and most effective way of securing the information. This paper considers popular and progressive security architectures available and used to-date, whilst focusing on authentication. Authentication can be defined as a security mechanism, the use of which allows the identity of a node in the network to be identified as a valid node of the network. Data authenticity can be achieved when a valid node decrypts the appended message authentication code, or applies one to an outgoing packet, using some known/shared key. Node authentication can be achieved using a number of different methods. A comparison table is presented which illustrates the various properties held by these security protocols, including authentication characteristics. This will allow the desirable characteristics of the various security architectures to be easily identifiable to designers in their struggle to implement the most cost effective and appropriate method of securing their network. <s> BIB005 </s> Overcoming Adversaries in Sensor Networks: A Survey of Theoretical Models and Algorithmic Approaches for Tolerating Malicious Interference <s> A. The Scope of this Survey <s> Wireless sensor networks (WSNs) use small nodes with constrained capabilities to sense, collect, and disseminate information in many types of applications. As sensor networks become wide-spread, security issues become a central concern, especially in mission-critical tasks. In this paper, we identify the threats and vulnerabilities to WSNs and summarize the defense methods based on the networking protocol layer analysis first. Then we give a holistic overview of security issues. These issues are divided into seven categories: cryptography, key management, attack detections and preventions, secure routing, secure location security, secure data fusion, and other security issues. Along the way we analyze the advantages and disadvantages of current secure schemes in each category. In addition, we also summarize the techniques and methods used in these categories, and point out the open research issues and directions in each area. <s> BIB006 </s> Overcoming Adversaries in Sensor Networks: A Survey of Theoretical Models and Algorithmic Approaches for Tolerating Malicious Interference <s> A. The Scope of this Survey <s> Jamming represents the most serious security threat in the field of wireless sensor networks (WSNs), as it can easily put out of order even WSNs that utilize strong highlayer security mechanisms, simply because it is often ignored in the initial WSN design. The objective of this article is to provide a general overview of the critical issue of jamming in WSNs and cover all the relevant work, providing the interested researcher pointers for open research issues in this field. We provide a brief overview of the communication protocols typically used in WSN deployments and highlight the characteristics of contemporary WSNs, that make them susceptible to jamming attacks, along with the various types of jamming which can be exercised against WSNs. Common jamming techniques and an overview of various types of jammers are reviewed and typical countermeasures against jamming are also analyzed. The key ideas of existing security mechanisms against jamming attacks in WSNs are presented and open research issues, with respect to the defense against jamming attacks are highlighted. <s> BIB007 </s> Overcoming Adversaries in Sensor Networks: A Survey of Theoretical Models and Algorithmic Approaches for Tolerating Malicious Interference <s> A. The Scope of this Survey <s> Among the most critical issues of wireless ad hoc and sensor networks are energy consumption in general and interfer-ence in particular. The reduction of interference is consequently considered one of the foremost goals of topology control. Almost all of the related work however considers this issue implicitly: Low interference is often claimed to be a consequence of sparseness or low degree of the constructed topologies. This paper, in contrast, studies explicit definitions of interference. Various models of in-terference--both from a sender-centric and a receiver-centric per-spective--are proposed, compared, and analyzed with respect to their algorithmic properties and complexities. <s> BIB008
There exist several survey papers on wireless sensor networks BIB001 - BIB002 and, more specifically, on security  - BIB006 , BIB005 - BIB007 . This existing literature presents a valuable categorization of attacks and practical security considerations. Framing results from the domain of sensor networks is difficult, not only due to the voluminous amount of work, but also because of the differing network models that have been adopted by the research community as surveyed in BIB004 , BIB008 and briefly highlighted in  . This issue is treated by both Raman and Chebrolu  and Chockler et al. BIB003 who provide an important discussion on the incongruity between the domains of theory and practice. In the context of adversarial attacks, this schism is particularly evident and we believe that a number of results belonging to the former domain are conspicuously absent from existing survey works. Here, we address this omission by surveying the literature on adversarial fault tolerance with an eye towards results with a theoretical flavor. Specifically, we examine models of adversarial interference where at least one of the following 1553-877X/11/$25.00 c 2011 IEEE is present: (1) jamming attacks (also known as denial-ofservice attacks), (2) Byzantine faults and adversarially chosen crash failures, and (3) spoofing or message injection attacks. Our overall aim is three-fold. First, we report on the adversarial models present in the literature with a focus on structuring them according to several underlying features and assumptions. This allows for a sensible comparison of models that are conceptually similar and delineate trade-offs between models that differ. Second, given this framework, we present an overview of the upper and lower bound results that accompany these models with respect to adversarial fault tolerance, message and bit complexity, communication latency and energy efficiency. In this sense, our focus is on models that admit provable bounds, in contrast to techniques aimed at mitigating adversarial behavior in practice. Third, as the area of adversarial fault tolerance in sensor networks is relatively new and still the subject of intense interest, we illustrate the progression of results and highlight directions for future work. Admittedly, the application of our criteria for examining a work is not always clear and the boundaries of our investigation may blur at times. For completeness, this survey incorporates a large number of results outside our focus that are dedicated to various aspects of adversarial fault tolerance. This includes work spanning purely experimental work on the real-world impact of malicious behavior to the taxonomies of adversarial attacks to the practicalities of currently implemented fault-tolerant techniques. We also note that there exists a substantial body of work regarding the application of game theory to this area (see the survey by Manshaei et al.  ); however, here we focus on worst-case adversarial settings where the participants may not act rationally. While these other results are not central to our survey, they are by no means tangential to the area of adversarial fault tolerance in sensor networks, and our work serves a dual purpose as a pointer to in-depth resources on these topics. The bulk of this survey is dedicated to a core subset of papers that we believe constitutes a cohesive body of work and meets the criteria described above, but has not yet received the comprehensive summary it deserves. A Roadmap: The remainder of this survey is comprised of three main sections. Section II provides the preliminaries for establishing the context in which we examine the core papers of this survey. Here, we address several important aspects of the design space for sensor network models such as assumptions regarding synchronization, collision detection, cryptography, and the different types of adversaries. In the process, we touch on a number of empirical studies and results from applied research fields in the area of mitigating adversarial interference. We also briefly describe several fundamental communication problems that arise in a number of the works we survey and enumerate the important metrics used to compare and contrast related results. In Section III, we focus on adversaries that aim to disrupt network functionality by jamming the communication channels. Due to the shared medium, such attacks are easily launched and require no special hardware to execute. Consequently, this type of behavior represents a simple denial-ofservice (DoS) attack that threatens the availability of sensor networks. We survey papers dedicated to examining the limits of such attacks and a number of possible algorithmic solutions. This is an area which has witnessed a flurry of work over the past several years and, consequently, a number of different models have been proposed and the question of which design aspects are most appropriate remains unresolved. In light of this, one of our aims is to convey the progression of the problems tackled by the research community. We highlight both the virtues and shortcomings of these results and offer a discussion of potential areas for future research. In Section IV, our attention shifts to Byzantine adversaries and, specifically, the problem of Byzantine agreement in multi-hop sensor networks. In this context, the problem has sometimes been referred to by the lengthy designations of reliable broadcast tolerating Byzantine adversarial behavior or reliable broadcast tolerating Byzantine faults. Throughout, we will assume the presence of a Byzantine adversary and, as is typical in many works, employ the simpler title of reliable broadcast. This is a problem that has received significant interest by the research community over the past half-decade and we note that the results covered in this section are not fully disjoint from those in Section III as jamming-tolerant reliable broadcast is addressed. Again, we attempt to convey the evolution of results and there is a discussion of the different models surveyed as well as an exploration of avenues of future research.