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Increasing base station anonymity using distributed beamforming
... Distributed beamforming has been exploited as a means for countering traffic analysis attacks [50,51]. The idea is to prevent an adversary from relating a communicating pair. ...
... Distributed beamforming allows the reduction of the transmission power of the source node S by 10log(| R| + 1) dB, where R is the set of cooperative relays [50]; however, this power savings for S does not characterize the total across the network as relays will incur overhead. The aggregated power usage for the transmission is dependent on the coordination overhead and data payload size. ...
... The aggregated power usage for the transmission is dependent on the coordination overhead and data payload size. It has been shown in [50] that the overall transmission power for ideal signal reception signal at the destination D while involving relays ∈ R is: ...
A Radiometric signature refers to transceiver specific features that are caused by variations in the manufacturing process even for the same circuit design. While such a radiometric signature constitutes a fingerprint that can be exploited for device authentication, it is a threat to privacy. Particularly, in the realm of wireless networks, an adversary may exploit radio frequency (RF) fingerprinting to identify devices and conduct traffic analysis in order to uncover the topology and categorize the role of various nodes. In this paper, we show how an adversary could employ RF fingerprinting to distinguish among nodes and bypass the provisioned anonymity protection in the network. We analyze the accuracy of RF fingerprinting and highlight how the accuracy affects the success of adversary attacks. To counter such a threat, we propose a novel methodology that requires no hardware changes to the radio transceiver and the associated host device. Our methodology is based on coordinated switching among preset link-layer and physical-layer communication protocols. For the latter, we particularly exploit distributed beamforming. We employ adversarial machine learning to select the protocol configuration for each transmission so that the accuracy of the RF fingerprinting diminishes. We demonstrate the effectiveness of our scheme through simulation and prototype experiments.
... Recently, [63] suggested the use of beamforming, to boost the anonymity of the base station while minimizing the communication energy overhead. In [63], distributed beamforming by nodes with single antennas cooperate to form a virtual multi-antenna system, to improve the communication range, data rate, energy efficiency, and security of the physical layer, and to decrease signal interference. ...
... Recently, [63] suggested the use of beamforming, to boost the anonymity of the base station while minimizing the communication energy overhead. In [63], distributed beamforming by nodes with single antennas cooperate to form a virtual multi-antenna system, to improve the communication range, data rate, energy efficiency, and security of the physical layer, and to decrease signal interference. The distributed beamforming technique is deployed as three components: a cross-layer relay selection algorithm, to determine which nodes will participate in the beamforming; a time synchronization algorithm, to construct a common time reference; and a carrier synchronization algorithm, to create a common frequency reference. ...
... Network nodes transmission power / range increase [62] Raising the transmission power of nodes increases the correlation between neighboring nodes and makes traffic analysis more difficult. Distributed beamforming [63] Beamforming boosts base station anonymity; low communication overhead. Randomized traffic volumes [65]: ...
The advent of miniature biosensors has generated numerous opportunities for deploying wireless sensor networks in healthcare. However, an important barrier is that acceptance by healthcare stakeholders is influenced by the effectiveness of privacy safeguards for personal and intimate information which is collected and transmitted over the air, within and beyond these networks. In particular, these networks are progressing beyond traditional sensors, towards also using multimedia sensors, which raise further privacy concerns. Paradoxically, less research has addressed privacy protection, compared to security. Nevertheless, privacy protection has gradually evolved from being assumed an implicit by-product of security measures, and it is maturing into a research concern in its own right. However, further technical and socio-technical advances are needed. As a contribution towards galvanising further research, the hallmarks of this paper include: (i) a literature survey explicitly anchored on privacy preservation, it is underpinned by untangling privacy goals from security goals, to avoid mixing privacy and security concerns, as is often the case in other papers; (ii) a critical survey of privacy preservation services for wireless sensor networks in healthcare, including threat analysis and assessment methodologies; it also offers classification trees for the multifaceted challenge of privacy protection in healthcare, and for privacy threats, attacks and countermeasures; (iii) a discussion of technical advances complemented by reflection over the implications of regulatory frameworks; (iv) a discussion of open research challenges, leading onto offers of directions for future research towards unlocking the door onto privacy protection which is appropriate for healthcare in the twenty-first century.
... As shown in Table 1, the first transmission from node S1 to node S2 allows the adversary to increment the evidences pointing to cells 0, 2, 9, 10, and 11. The same is done when the packet is retransmitted by intermediate node S2, adding an evidence pointing to cells 1, 2, 3, 10, 12, 19, 20 and 21, and similarly for the transmission from node S3, implying an evidence for the possible existence of a link between cell 20 and cells 10,11,12,19,21,28,29, and 30. The adversary correlates the suspected links and derives new evidences as shown in Table 1 in order to draw a set of possible end-to-end paths. ...
... 1 E(1,0), E(1,2), E (1,9), E(1,10), E(1,11) 1 0.2 0.0714 11 E(11,1), E (11,2), E (11,3), E (11,10), E (11,12), E (11,19), E (11,20), E (11,21) 1 0.125 0.1428 20 E (20,10), E (20,11), E (20,12), E (20,19), E (20,21), E (20,28), E (20,29), E (20,30) 1 0.125 0.0714 ...
... 1 E(1,0), E(1,2), E (1,9), E(1,10), E(1,11) 1 0.2 0.0714 11 E(11,1), E (11,2), E (11,3), E (11,10), E (11,12), E (11,19), E (11,20), E (11,21) 1 0.125 0.1428 20 E (20,10), E (20,11), E (20,12), E (20,19), E (20,21), E (20,28), E (20,29), E (20,30) 1 0.125 0.0714 ...
... In [11], Ward and Younis proposed a physical-layer (PHY) approach that leverages distributed beamforming to increase the BS's anonymity. Distributed beamforming has recently received attention as a method for improving the communication range, data rate, and energy efficiency, providing physical-layer security, and reducing interference in distributed wireless networks [12]. ...
... Previous foundational analyses demonstrated that distributed beamforming can successfully increase the BS anonymity, but these analyses limited the attack model by considering an unwitting adversary that was unaware of distributed beamforming being applied to the WSN [11]. This constraint is too conservative because both the control traffic associated with the recruitment of distributed beamforming helper relays and the inherent focused, narrow beamwidth transmission produced by cooperating nodes provide an eavesdropping adversary with indicators that distributed beamforming is being used as an anonymity-boosting technique. ...
... Mudumbai et al. [14] presented an overview of the current state of the art, challenges, and successful implementations of distributed beamforming systems. In [15], the same authors describe a master-slave carrier frequency synchronization architecture, which is leveraged in our DiBAN distributed beamforming protocol [11]. Quitin et al. [16] and Rahman et al. [17] present practical implementations and analyses of distributed beamforming systems using GNU Radio and Universal Software Radio Peripheral (USRP). ...
In most Wireless Sensor Network (WSN) applications the sensor nodes forward their measurements to a central base station (BS). The unique role of the BS makes it a natural target for an adversary’s attack. Even if a WSN employs conventional security mechanisms such as encryption and authentication, an adversary may apply traffic analysis techniques to locate the BS. This motivates a significant need for improved BS anonymity to protect the identity, role, and location of the BS. Previous work presented distributed beamforming as a very effective anonymity-boosting technique. However, such work assumed that the adversary is unaware of the countermeasure, and thus the anonymity performance could be unattainable. In this paper we extend our preliminary work from Ward and Younis (Proceedings of the IEEE military communications conference (MILCOM 2016), Baltimore, MD, 2016) to show that the adversary could adapt the attack strategy when knowing of the use of distributed beamforming. We analyze two strategies for such an adaptive attack, one using Evidence Theory and one using Traffic Volume. We then develop a cross-layer countermeasure that incorporates distributed beamforming to successfully misdirect such an adaptive adversary and boost BS anonymity. The effectiveness of our approach is validated through simulation.
... In [7][8], Ward and Younis proposed a physical-layer (PHY) approach that leverages distributed beamforming to increase the BS's anonymity. Distributed beamforming has recently received attention as a method for improving the communication range, data rate, and energy efficiency, providing physical-layer security, and reducing interference in distributed wireless networks [9] [10]. ...
... For example, under ideal conditions transmitters that send identical messages using equal power while incurring similar path loss when transmitting to a common destination will achieve a factor of increase in power at that destination. This property has been demonstrated to increase BS anonymity when applied to a WSN using our Distributed Beamforming protocol for increased BS ANonymity (DiBAN) [7]. DiBAN successfully corrupts the adversary's Evidence Theory (ET) analysis such that the actual BS is not implicated as the WSN's sink. ...
... To the authors' knowledge, using cooperative communication to boost the BS anonymity was first published in [7]. Meanwhile, other studies have not investigated customized routing protocols for distributed beamforming systems. ...
... Multiple nodes transmit simultaneously, accounting for wireless channel conditions and precisely control the signal phase, such that all signals constructively combine at the destination. This property has been demonstrated to increase BS anonymity when applied to a WSN using our Distributed Beamforming protocol for increased BS ANonymity (DiBAN) [8]. DiBAN successfully corrupts a traditional, non-adaptive adversary's traffic analysis using models like Evidence Theory (ET) [5] [6] such that the BS is not implicated as the WSN's sink. ...
... The anonymity-boosting techniques of [11] - [15] are based on establishing paths between fake sources and sinks to increase transmissions in the WSN to distract the adversary. Finally the DiBAN PHY approach [8] exploits distributed beamforming to boost BS anonymity. Our crosslayer A 2 C 2 , described in Section VI, integrates the key concepts of [10][15] [16] within DiBAN to boost anonymity in the presence of an adaptive adversary. ...
... The DiBAN protocol, proposed in [8], satisfies these three requirements such that a WSN may successfully implement distributed beamforming. We represent the ideal received signal at that is transmitted by source and | | helper relays as: ...
... Existing BS anonymity boosting techniques can be classified according to which layer of the communication protocol stack they are applied at. At the physical layer, Ward and Younis [30,31] propose to de-associate the receiver from the sender using distributed beamforming in order to extend the transmission range and make it difficult for an adversary to infer the relationship between a sender and a receiver. The proposed countermeasure is based on the use of helper relays that transmit the message of the source in a coordinated and synchronized manner so that the radio signals of multiple transmissions are combined and reach the receiver. ...
In wireless sensor networks (WSNs), the base station plays a major role in processing and transmitting collected data to the command centers. Given its critical role, it is considered as the most important part in the network and hence becomes a target of an adversary attack. Although many solutions have been proposed to prevent the base station (BS) from exposing itself, the traffic pattern in the network degrades the BS location anonymity and makes it vulnerable. In this paper, we propose a Multi-Illusive Voids approach for increasing the Base Station Anonymity (MIVA). MIVA exploits the features of geographic routing to both confuse the adversary about the routing topology and to have some control over the adversary’s Belief. Specifically, MIVA forms a fake void around the BS in order to avert the adversary’s attention away from the BS vicinity and the multiple other fake voids throughout the network to confuse the adversary about a potential location for the BS. MIVA is validated through simulation and is shown to outperform prominent competing anti-traffic analysis techniques.
... Meanwhile the bulk of the published anonymity boosting techniques are applicable at the network layer. Many routing protocols have been proposed to sustain ID anonymity by ciphering the routing information, employing label switching, etc. [7][8] [11]; yet they cannot guard the network against traffic analysis that correlates intercepted frames rather than packets. As we pointed out earlier an adversary can eavesdrop and locate a radio transmitter even if the message cannot be demodulated and decoded. ...
The Internet of Things (IoT) refers to the internetworking of diverse devices in an ad-hoc manner to support pervasive applications. IoT devices often generate a wealth of data that ought to be accessible and managed in a distributed manner. Such operational model requires architecture that supports contextual and information centric retrieval of data, and efficient data storage. In this paper, we argue that peer-to-peer (P2P) overlays are well suited for IoT systems. However, existing P2P systems do not efficiently handle queries of data within a range, which is a popular access pattern in IoT applications. Moreover, many of the IoT devices are constrained in their computational resources and consequently the data management model has to cope with such limitation. Existing P2P solutions do not factor the heterogeneity of the involved nodes and assume abundant storage space. This paper opts to fill the technical gap and proposes an effective P2P solution for efficient handling of range queries in IoT (RQIOT). RQIOT employs a data distribution model based on both consistent and order-preserving hashing and introduces a novel scheme for capacity management of the involved devices. The simulation results have confirmed the effectiveness and scalability of RQIOT, and the superiority of its performance over competing approaches.
... The proposed approach [36], which is based on Advanced Encryption Standard (AES), evaluates the Peak Signal to Noise Ratio (PSNR) for encrypted and decrypted frames, and the PSNR required by the encrypted multimedia data requires is about 1 3 of the decrypted data. In [37], with Distributed Beamforming protocol for increased BS ANonymity (DiBAN) [51], the proposed approach can increase the anonymity of BS. ...
Cross-Layer Design has proven much precedented significance in the development of heterogeneous networks. Its excellence is seen at the comprehensive involvement of all the related layers. The core principle of cross-layer design is supported by the exchange of information between layers through exploiting their inter-cooperation, so as to bring about a series of benefits for the advancement of networking technology, such as producing more adaptivity and predictability. Without exception, Wireless Sensor Networks (WSNs) demand cross-layer design, and its effectiveness in this area has been widely indicated in numerous studies. Especially, since WSN works on non-fixed infrastructure and under various constraints, the traditional layering approach, which limits the coordination between layers, impairs the flexibility and the performance of WSNs. Therefore, cross-layer design, by taking the advantages of capability and relationship across layers, can significantly increase the overall performance of WSNs. Nonetheless, as a complex approach, cross-layer design in WSNs takes every detail into account, and hence unavoidably, encounters a heap of explicit and potential issues. Regarding the problems of cross-layer design in WSNs, the contribution to searching the apposite solution keeps brisk, therefore, investigating the issues and solutions of cross-layer design in sensor networks is required for the sustainable progress of these two technologies and their integrated application. In this paper, based on the principle of cross-layer design and the architecture of WSNs, the survey of relevant issues and solutions will be unfolded, with the aim of providing a valuable reference for further study.
... Then, the sink collects these packets and sends them to the network manager. Such many-to-one communication pattern makes the sink the central point of failure [3,4]. An attacker could destroy the sink physically after tracing and locating it and hence paralyze the whole sensor network. ...
Sink location protection is critical to the viability of sensor networks as the central point of failure. Most existing work related to sink location protection focuses on local traffic analysis attack. In this paper, we study the sink location protection problem under a more powerful type of attack, the global traffic analysis attack. In order to hide the sink location, a protocol based on packet sending rate adjustment (SRA) is proposed. By controlling the packet sending rate of each node according to the current number of source nodes, SRA conceals the real traffic volume generated by source nodes and hence disguises the location of the sink. For further reducing the communication cost, we propose a light weight SRA protocol (L-SRA), which protects the sink location while significantly decreasing the communication cost. Performance of both SRA and L-SRA has been validated by theoretical analysis and simulation results.
The Internet of Things (IoT) is regarded as one of the most promising fields for ubiquitous access, information exchange, and real-time analysis. The enormous device population and direct interactions among devices help form social attributes of devices, enabling Social IoT (SIoT) that integrates an IoT system and Social Networks. Despite advantages including network navigability, service scalability, and enhanced trustworthiness of data, there are more severe security issues to be solved urgently in SIoT. We first depict a powerful SIoT and abstract primary social attributes, then present key security issues in SIoT and investigate specific solutions via cross-layer. The core of cross-layer designs is the tradeoff between security and other aspects (e.g., energy or complexity) in essence. Moreover, graph-powered learning has shown its superiority in Social Networks, leading to our discussion about applying graph learning in SIoT cross-layer security schemes for promoting future SIoT security researches.
Concepts and Main Types of Sensors and Platforms and Communication Protocols;
Regulatory decisions on remediation should consider affected communities' needs and values, and how these might be impacted by remedial options; this process requires that diverse stakeholders are able to engage in a transparent consideration of value trade-offs and of the distribution of risks and benefits associated with remedial actions and outcomes. The Stakeholder Values Assessment (SVA) tool was developed to evaluate remedial impacts on environmental quality, economic viability and social equity in the context of stakeholder values and priorities. Stakeholder values were linked to the pillars of sustainability and also to a range of metrics to evaluate how sediment remediation affects these values. Sediment remedial alternatives proposed by the USEPA for the Portland Harbor Superfund Site were scored for each metric, based upon data provided in the feasibility study (FS) documents (AnchorQEA 2012; USEPA 2016a); metric scores were aggregated to generate scores for each value; these were then aggregated to generate scores for each pillar of sustainability. In parallel, the inferred priorities (in terms of regional remediation, restoration, planning, and development) of diverse stakeholder groups (SGs) were used to evaluate the sensitivity and robustness of the values-based sustainability assessment to diverse SG priorities. This approach, which addresses social indicators of impact and then integrates them with indicators of environmental and economic impacts, goes well beyond the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) 9 criteria for evaluating remedial alternatives because it evaluates how remedial alternatives might be ranked in terms of the diverse values and priorities of stakeholders. This approach identified trade-offs and points of potential contention, providing a systematic, semi-quantitative, transparent valuation tool which can be used in community engagement. This article is protected by copyright. All rights reserved.
Distributed and collaborative beamforming (DCBF) scheme in wireless sensor networks (WSNs) is receiving new-found interest in recent times due to the rapid advancements in wireless technology and embedded systems. Although studies on distributed and collaborative beamforming have been carried out for more than ten years, the DCBF was initially considered impractical due to high complexity and hardly achievable requirements. It gained prominence only in the past few years as small wireless communication electronic sensors with high processing capability became easily available. Recent works showcasing distributed and collaborative beamforming as a suitable solution for 5G communication systems such as mm-wave communication and machine to machine (M2M) communications has further ignited the interest in this research field. Motivated by these factors, this article presents a survey on the research trends of distributed and collaborative beamforming in WSNs. We provide classifications of the DCBF research areas and conduct an extensive review of the various proposals which have appeared in the literature for each classification. This survey uncovered that majority of existing research can be broadly divided into four major research trends: beampattern analysis, power and lifetime optimization, synchronization and finally prototype design. The inherent features, constraints and challenges of each research category in the distributed and collaborative beamforming are presented and the lessons learned from the shortcomings of previous research are summarized. Finally, this survey has unveiled open research directions in the field of distributed and collaborative beamforming in WSNs.
By more and more, privacy preservation problem is widely discussed among users and researchers. For mobile sensing network, an imperfect privacy preservation scheme will directly put participants into a dangerous situation. The better privacy protection applied, the better sensing data quality will be achieved. In this paper, we present a privacy-aware data aggregation scheme for mobile sensing networks. We considered both the smart nodes like smart-phone and dumb nodes like wearable device or GPS device. We take the location information and the sensing content into consideration separately. And this thought will make sure the sensing content will be k-anonymous and the accurate location will be protected well either. We use erasure coding technology to slice the sensing data record according to the k-anonymity rules. For the sake of efficiency and stability, we compare two coding technology in two sensing data types and give the experiment results and explanations in detail. After that, we give a social model to describe the social relation and a security data sharing protocol among the participants. The introduction of the participants’ social relation may give a new way to the reputation and data trustworthy evaluation mechanism.
In recent years, Wireless Sensor Networks (WSNs) have become valuable assets to both the commercial and military communities with applications ranging from industrial automation and product tracking to intrusion detection at a hostile border. A typical WSN topology allows sensors to act as data sources that forward their measurements to a central sink or base station (BS). The unique role of the BS makes it a natural target for an adversary that desires to achieve the most impactful attack possible against a WSN. An adversary may employ traffic analysis techniques to identify the BS based on network traffic flow even when the WSN implements conventional security mechanisms. This motivates a need for WSN operators to achieve improved BS anonymity to protect the identity, role, and location of the BS. Although a variety of countermeasures have been proposed to improve BS anonymity, those techniques are typically evaluated based on a WSN that does not employ acknowledgements. In this paper we propose an enhanced evidence theory metric called Acknowledgement-Aware Evidence Theory (AAET) that more accurately characterizes BS anonymity in WSNs employing acknowledgements. We demonstrate AAET's improved robustness to a variety of configurations through simulation.
In recent years, Wireless Sensor Networks (WSNs) have become valuable assets to both the commercial and military communities with applications ranging from industrial control on a factory floor to reconnaissance of a hostile border. A typical WSN topology that applies to most applications allows sensors to act as data sources that forward their measurements to a central sink or base station (BS). The unique role of the BS makes it a natural target for an adversary that desires to achieve the most impactful attack possible against a WSN. An adversary may employ traffic analysis techniques such as evidence theory to identify the BS based on network traffic flow even when the WSN implements conventional security mechanisms. This motivates a need for WSN operators to achieve improved BS anonymity to protect the identity, role, and location of the BS. Location anonymity assessments depend on an adversary's ability to achieve accurate range estimates to map intercepted traffic to the target network's topology. These range estimates may suffer from a variety of errors depending on the specific RF propagation environment in which the target system operates. BS anonymity estimates in turn may be degraded depending on the severity of the ranging errors. In this paper we examine the effect of Gaussian distributed ranging errors on BS anonymity using evidence theory analysis and simulation.
Wireless Sensor Networks (WSNs) often operate in inhospitable environments to serve mission-critical and security-sensitive applications that involve hostile adversaries. These adversaries are eager to disrupt the WSN operation. Given the important role that the base-station (BS) plays in a WSN, the adversary opts to identify the BS and determine its location in order to damage the BS or launch a targeted denial of service attack. Therefore, maintaining the BS anonymity is of utmost importance in WSNs. Even if the adversary cannot decode packets, correlating the intercepted transmission through traffic analysis can reveal the position of the BS. This paper considers setups in which the network has multiple base-stations and proposes a novel approach in which these base-stations collaborate on confusing the adversary and averting attacks. The proposed Multi-player Anonymity optimization Game theoretic (MAG) approach calls for the introduction of inter-BS deceptive traffic and use game theory to determine the volume and destination of such traffic so that the variance in the location anonymity over all BSs is reduced. The simulation results demonstrate the effectiveness of MAG.
In wireless sensor networks, all data packets are routed from the individual sensor nodes towards an in-situ base-station (BS). Such traffic pattern makes the BS vulnerable to adversary's attack. Basically, an adversary would intercept the ongoing transmissions and localize their sources. Then by employing traffic analysis techniques, an adversary would correlate the intercepted transmissions to uncover the data path which may lead to the location of the BS. Evidence theory is a well-known scheme that an adversary might use for traffic analysis. However, prior work considered only intercepted transmissions as evidences in the correlation process without factoring in the time of interception. In this paper, we argue that time-based correlation increases the accuracy of the traffic analysis and makes contemporary countermeasures ineffective. A novel technique is proposed to counter the time correlation and boost the anonymity of the BS. The technique imposes buffering delay at each relaying node on the data route in order to disturb the time correlation among consecutive transmissions. Our technique is validated through simulation.
In recent years, Wireless Sensor Networks (WSNs) have become valuable assets to both the commercial and military communities with applications ranging from industrial control on a factory floor to reconnaissance of a hostile border. In most applications, the sensors act as data sources and forward information generated by event triggers to a central sink or base station (BS). The unique role of the BS makes it a natural target for an adversary that desires to achieve the most impactful attack possible against a WSN with the least amount of effort. Even if a WSN employs conventional security mechanisms such as encryption and authentication, an adversary may apply traffic analysis techniques to identify the BS. This motivates a significant need for improved BS anonymity to protect the identity, role, and location of the BS. In this paper we propose a novel cross-layer relay-selection algorithm and a distributed beamforming protocol to increase BS anonymity. We examine the effect of the proposed distributed beamforming technique on improving BS anonymity using evidence theory analysis and demonstrate the effectiveness of this approach through simulation.
We describe a fully-wireless prototype of distributed transmit beamforming on a software-defined radio platform. Distributed beamforming is a cooperative transmission technique that can achieve orders of magnitude increases in range or energy efficiency of wireless communication systems. However, this technique requires precise synchronization of the radio frequency signal from each transmitter. The significance of our prototype is in demonstrating that this requirement can be satisfied using digital signal processing methods on commodity hardware with low-quality oscillators. Our synchronization approach scales to large numbers of transmitters: each transmitter runs independent algorithms based on periodically transmitted feedback packets from the receiver. A key simplification is the decoupling of the algorithms for frequency locking and beamsteering at each transmitter, even though both processes use the same feedback packets. Frequency locking employs an Extended Kalman filter to track the local oscillator offset between a transmitter and the receiver, using frequency offset measurements based on the feedback packet it waveform, while the phase adjustments for beamsteering are determined using a one-bit feedback algorithm based on the feedback packet it payload. Our prototype demonstrates that distributed transmit beamforming can be incorporated into wireless networks without requiring hardware innovations, and provides open-source building blocks for future research and development.
Localization techniques that allow inferring the location of wireless devices directly from received signals have exposed mobile users to new threats. Adversaries can easily collect required information (such as signal strength) from target users, however, techniques securing location information at the physical layer of the wireless communication systems have not received much attention. In this paper, we propose Phantom, a novel approach to allow mobile devices thwart unauthorized adversary's location tracking by creating forged locations. In particular, Phantom leverages cooperation among multiple mobile devices in close vicinity and utilizes synchronized transmissions among those nodes to obfuscate localization efforts of adversary systems. Through an implementation on software-defined radios (GNU Radios) and extensive simulation with real location traces, we see that Phantom can improve location privacy.
We describe the key ideas behind our implementation of distributed beamforming on a GNU-radio based software-defined radio platform. Distributed beamforming is a cooperative transmission scheme whereby a number of nodes in a wireless network organize themselves into a virtual antenna array and focus their transmission in the direction of the intended receiver, potentially achieving orders of magnitude improvements in energy efficiency. This technique has been extensively studied over the past decade and its practical feasibility has been demonstrated in multiple experimental prototypes. Our contributions in the work reported in this paper are three-fold: (a) the first ever all-wireless implementation of distributed beamforming without any secondary wired channels for clock distribution or channel feedback, (b) a novel digital baseband approach to synchronization of high frequency RF signals that requires no hardware modifications, and (c) an implementation of distributed beamforming on a standard, open platform that allows easy reuse and extension. We describe the design of our system in detail, present some initial results and discuss future directions for this work.
This work investigates the lower bounds of wireless localization accuracy using signal strength on commodity hardware. Our work relies on trace-driven analysis using an extensive indoor experimental infrastructure. First, we report the best experimental accuracy, twice the best prior reported accuracy for any localization system. We experimentally show that adding more and more resources (e.g., training points or landmarks) beyond a certain limit, can degrade the localization performance for lateration-based algorithms, and that it could only be improved further by "cleaning" the data. However, matching algorithms are more robust to poor quality RSS measurements. We next compare with a theoretical lower bound using standard Cramer Rao Bound (CRB) analysis for unbiased estimators, which is frequently used to provide bounds on localization precision. Because many localization algorithms are based on different mathematical foundations, we apply a diverse set of existing algorithms to our packet traces and found that the variance of the localization errors from these algorithms are smaller than the variance bound established by the CRB. Finally, we found that there exists a wide discrepancy from what free- space models predict in the signal to distance function even in an environment with limited shadowing and multipath, thereby imposing a fundamental limit on the achievable localization accuracy indoors.
Distributed transmit beamforming is a form of cooperative communication in which two or more information sources simultaneously transmit a common message and control the phase of their transmissions so that the signals constructively combine at an intended destination. Depending on the design objectives and constraints, the power gains of distributed beamforming can be translated into dramatic increases in range, rate, or energy efficiency. Distributed beamforming may also provide benefits in terms of security and interference reduction since less transmit power is scattered in unintended directions. Key challenges in realizing these benefits, however, include coordinating the sources for information sharing and timing synchronization and, most crucially, distributed carrier synchronization so that the transmissions combine constructively at the destination. This article reviews promising recent results in architectures, algorithms, and working prototypes which indicate that these challenges can be surmounted. Directions for future research needed to translate the potential of distributed beamforming into practice are also discussed.
In a wireless sensor network nodes probe ambient conditions and send the measurements over multi-hop routes to a base-station. The base-station aggregates the received reports, and based on the findings it orchestrates a response either autonomously or through consultation with a remote commend center. Thus, the role of the base-station is so crucial that the network can be non-functional and/or isolated if the base-station breaks down or gets destroyed. No wonder in a hostile environment, an adversary will target the base-station to inflict the most damage to the network. The fact that the base-station acts as a sink of all data traffic makes it vulnerable to attacks by tracking packet transmission and detecting its location. This paper investigates a novel strategy to counter traffic analysis and boosts the anonymity of the base-station. A sensor transmits at a higher power in order to increase its number of neighbors and confuse an adversary who is assessing the linkability of nodes in quest to identify the route to the base-station. Both analytical and simulation results are provided to capture the effect of increased transmission power on the base-station anonymity.
Sensor networks are used in a variety of application ar- eas for diverse problems from habitat monitoring to mil- itary tracking. Whenever they are used to monitor sen- sitive objects, the privacy of monitored objects' locations becomes an important concern. When a sensor reports a monitored object by sending a series of messages through the sensor network, the route these messages take in the- ory creates a trail leading back to their source. By eaves- dropping on communications, an attacker may be able to move from node to node to follow this trail. Several ap- proaches aimed at discouraging this kind of eavesdropping have been proposed, including mechanisms for constructing "phantom" routes and approaches that insert fake sources as background noise. A problem with existing approaches is that message latencies become larger and energy costs become higher as a result of introducing protections for the privacy of a source location. This paper proposes a new cyclic entrapment method (CEM) that protects source loca- tions in sensor networks while adding a comparatively low cost in terms of additional message latency and energy.
As sensor-driven applications become increasingly integrated into our lives, issues related to sensor privacy will become increasingly important. Although many privacy-related issues can be addressed by security mechanisms, one sensor network privacy issue that cannot be adequately addressed by network security is confidentiality of the source sensor's location. In this paper, we focus on protecting the source's location by introducing suitable modifications to sensor routing protocols to make it difficult for an adversary to backtrack to the origin of the sensor communication. In particular, we focus on the class of flooding protocols. While developing and evaluating our privacy-aware routing protocols, we jointly consider issues of location-privacy as well as the amount of energy consumed by the sensor network. Motivated by the observations, we propose a flexible routing strategy, known as phantom routing, which protects the source's location. Phantom routing is a two-stage routing scheme that first consists of a directed walk along a random direction, followed by routing from the phantom source to the sink. Our investigations have shown that phantom routing is a powerful technique for protecting the location of the source during sensor transmissions.
In wireless sensor networks, nodes probe ambient conditions in their surrounding and report back to the base-station via multi-hop routing. In a hostile environment the network may be subject to adversary attacks. Given the role that the base-station plays, it can be targeted in order to inflict the most damage to the network. Although stealth design and other physical precautionary measures may be pursued to hide the base-station, the fact that the base-station acts as a sink of all data transmission enables an adversary to employ traffic analysis techniques and identify the location of the base-station. This paper presents a novel approach for countering such traffic analysis and boosting the anonymity of the base-station. Sensors in low activity areas will send out deceptive packets among each other in order to distract the attention of the adversary and make the traffic analysis inconclusive. Simulation results show the effectiveness of the approach.
Due to the nature of radio transmissions, communications in wireless networks are easy to capture and analyze. Next to this, privacy enhancing techniques (PETs) proposed for wired networks such as the Internet often cannot be applied to mobile ad hoc networks (MANETs). In this paper we present a novel anonymous on demand routing scheme for MANETs. We identify a number of problems of previously proposed works and propose an efficient solution that provides anonymity in a stronger adversary model.
One of the most notable challenges threatening the successful deployment of sensor systems is privacy. Although many privacy-related issues can be addressed by security mechanisms, one sensor network privacy issue that cannot be adequately addressed by network security is source-location privacy. Adversaries may use RF localization techniques to perform hop-by-hop traceback to the source sensor's location. This paper provides a formal model for the source-location privacy problem in sensor networks and examines the privacy characteristics of different sensor routing protocols. We examine two popular classes of routing protocols: the class of flooding protocols, and the class of routing protocols involving only a single path from the source to the sink. While investigating the privacy performance of routing protocols, we considered the tradeoffs between location-privacy and energy consumption. We found that most of the current protocols cannot provide efficient source-location privacy while maintaining desirable system performance. In order to provide efficient and private sensor communications, we devised new techniques to enhance source-location privacy that augment these routing protocols. One of our strategies, a technique we have called phantom routing, has proven flexible and capable of protecting the source's location, while not incurring a noticeable increase in energy overhead. Further, we examined the effect of source mobility on location privacy. We showed that, even with the natural privacy amplification resulting from source mobility, our phantom routing techniques yield improved source-location privacy relative to other routing methods
Cooperative diversity has been recently proposed as a way to form virtual antenna arrays that provide dramatic gains in slow fading wireless environments. However, most of the proposed solutions require distributed space-time coding algorithms, the careful design of which is left for future investigation if there is more than one cooperative relay. We propose a novel scheme that alleviates these problems and provides diversity gains on the order of the number of relays in the network. Our scheme first selects the best relay from a set of M available relays and then uses this "best" relay for cooperation between the source and the destination. We develop and analyze a distributed method to select the best relay that requires no topology information and is based on local measurements of the instantaneous channel conditions. This method also requires no explicit communication among the relays. The success (or failure) to select the best available path depends on the statistics of the wireless channel, and a methodology to evaluate performance for any kind of wireless channel statistics, is provided. Information theoretic analysis of outage probability shows that our scheme achieves the same diversity-multiplexing tradeoff as achieved by more complex protocols, where coordination and distributed space-time coding for M relay nodes is required, such as those proposed by Laneman and Wornell (2003). The simplicity of the technique allows for immediate implementation in existing radio hardware and its adoption could provide for improved flexibility, reliability, and efficiency in future 4G wireless systems.
distributed system. For years, protocols such as NTP (the Network Time Protocol) have kept the Internet's clocks ticking in phase. However, a new class of networks is emerging. Advances in miniaturization and low-cost, low-power design have led to active research in large-scale networks of small, wireless, low-power sensors and actuators. These systems are closely coupled to the physical world and have strict energy constraints; this leads to stronger accuracy and precision requirements while limiting the resources that can be used to achieve them. Is NTP the right choice for these new networks? We present Reference-Broadcast Synchronization (RBS), in which nodes send reference beacons to their neighbors using physical-layer broadcasts. A reference broadcast does not contain an explicit timestamp; instead, receivers use its arrival time as a point of reference for comparing their clocks. In this paper, we use measurements from two wireless implementations to show that removing the sender's nondeterminism from the critical path in this way results in a dramatic improvement in synchronization over using NTP. We also present an algorithm that allows time to be propagated across broadcast domains without losing the referencebroadcast property. In this way, nodes in a multi-hop network can form a highly precise relative timescale, or maintain microsecondlevel synchronization to an external timescale such as UTC.
The performance of collaborative beamforming is analyzed using the theory of random arrays. The statistical average and distribution of the beampattern of randomly generated phased arrays is derived in the framework of wireless ad hoc sensor networks. Each sensor node is assumed to have a single isotropic antenna and nodes in the cluster collaboratively transmit the signal such that the signal in the target direction is coherently added in the far- eld region. It is shown that with N sensor nodes uniformly distributed over a disk, the directivity can approach N, provided that the nodes are located sparsely enough. The distribution of the maximum sidelobe peak is also studied. With the application to ad hoc networks in mind, two scenarios, closed-loop and open-loop, are considered. Associated with these scenarios, the effects of phase jitter and location estimation errors on the average beampattern are also analyzed. Comment: To appear in the IEEE Transactions on Signal Processing
In recent years, Wireless Sensor Networks (WSNs) have become valuable assets to both the commercial and military communities with applications ranging from industrial control on a factory floor to reconnaissance of a hostile border. In both applications, the sensors act as data sources and forward information to a central sink or base station (BS). The unique role of the BS makes it a natural target for an adversary that desires to achieve the most impactful attack possible against a WSN with the least amount of effort. An adversary may employ traffic analysis techniques to identify the BS based on network traffic flow even when the WSN implements conventional security mechanisms. This motivates a significant need for improved BS anonymity to protect the identity, role, and location of the BS. In this paper we propose a strategy to increase BS anonymity in a WSN by utilizing multiple relays at each hop. Each relay retransmits received messages at an increased power level to increase the number of candidate receivers included in the adversary's analysis. We examine the effect of the distributed relay technique on improving BS anonymity using evidence theory and demonstrate the effectiveness of this approach through simulation.
Wireless communications systems are particularly vulnerable to security attacks because of the inherent openness of the transmission medium. In this article, we focus on guaranteeing confidentiality against eavesdropping attacks where an unauthorized entity aims to intercept an ongoing wireless communication, and we provide a comprehensive summary of recent advances in the area of physical-layer security that guarantees confidentiality by using cooperative techniques unique to the wireless medium. These cooperative techniques consist of carefully designed coding and signaling schemes that are able to harness the properties of the physical layer and to ensure some level of information-theoretic security.
Onion routing is an infrastructure for private communication over a public network. It provides anonymous connections that are strongly resistant to both eavesdropping and traffic analysis. Onion routing's anonymous connections are bidirectional, near real-time, and can be used anywhere a socket connection can be used. Any identifying information must be in the data stream carried over an anonymous connection. An onion is a data structure that is treated as the destination address by onion routers; thus, it is used to establish an anonymous connection. Onions themselves appear different to each onion router as well as to network observers. The same goes for data carried over the connections they establish. Proxy-aware applications, such as Web browsers and e-mail clients, require no modification to use onion routing, and do so through a series of proxies. A prototype onion routing network is running between our lab and other sites. This paper describes anonymous connections and their implementation using onion routing. This paper also describes several application proxies for onion routing, as well as configurations of onion routing networks
Anonymous MANET routing relies on techniques such as re-encryption on each hop to hide end-to-end commu- nication relations. However, passive signal detectors and traffic analyzers can still retrieve sensitive information from PHY and MAC layers to derive end-to-end communication relations through statistical traffic analysis. In this paper, we propose a Statistical Traffic pAttern discoveRy System (STARS) based on eigen analysis which can greatly improve the accuracy to derive traffic patterns in MANETs. STARS intends to find out the sources and destinations of captured packets and to discover the end-to-end communication relations. The proposed approach is purely passive. It does not require analyzers to be actively involved in MANET transmissions and to possess encryption keys to decrypt traffic. We present theoretical models as well as extensive simulations to demonstrate our solutions.
Smart grid will become the next-generation electrical power system to provide reliable, efficient, secure, and cost-effective energy generation, distribution, and consumption. To achieve these goals, communications infrastructure and wireless networking will play an important role in supporting data transfer and information exchange in smart grid. In this article, the application of cooperative transmission for the meter data collection in smart grid is introduced. In a service area of smart grid, there are multiple communities composed of power consumption nodes (e.g., houses). The power consumption demand from the nodes is measured by a smart meter and transmitted to a meter data management system (MDMS) through the data aggregator unit (DAU) using wireless broadband access. The community invests in and deploys a relay station to perform relay transmission to improve the transmission rate and avoid congestion at the DAU. As a result, the MDMS will have complete and correct power demand data, which can be used to make better decisions on power supply. Since the communities in a service area of smart grid are rational, they will optimize the relay transmission strategy so that the total cost (i.e., power cost and transmission cost) is minimized. To analyze the relay transmission strategy of the community, the noncooperative game model is formulated, and the Nash equilibrium is considered as the solution. The proposed network architecture and analysis will be useful for the design and optimization of a wireless network for smart grid.
At last--here's a comprehensive book that puts full details on all short-range wireless-positioning methods at your command for instant access and use. This one-stop resource surveys each technique's theory of operation, advantages and disadvantages, applicability in different domains, implementation procedures, and accuracy to help you select the right technology for any application and ensure the best results possible. Real-life examples together with 161 diagrams help bring all options into sharp focus. After introducing wireless positioning fundamentals along with various personal, commercial, and industrial applications, the book guides you step by step through radio signal time of flight methods, the signal strength method, the angle of arrival system, and the geometric use of distance measurement to determine location. It discusses location awareness applications and implementations using cellular networks. You are brought up to speed on fast-developing techniques involving local area networks (WLANs), personal area networks (WPANs), and radio frequency ID (RFID). Moreover, you find coverage of the distance measurement features in the new IEEE 802.15.4a spec for low rate wireless personal area networks. This practical resource offers detailed guidance on how to implement important technologies, including direct sequence spread spectrum, frequency hopping spread spectrum, and ultrawideband (UWB). The book also explores ways to counteract accuracy impairments caused by noise, multipath and fading, and limitations of antenna directivity and time measurement precision.
Ubiquitous sensing enabled by Wireless Sensor Network (WSN) technologies cuts
across many areas of modern day living. This offers the ability to measure,
infer and understand environmental indicators, from delicate ecologies and
natural resources to urban environments. The proliferation of these devices in
a communicating-actuating network creates the Internet of Things (IoT),
wherein, sensors and actuators blend seamlessly with the environment around us,
and the information is shared across platforms in order to develop a common
operating picture (COP). Fuelled by the recent adaptation of a variety of
enabling device technologies such as RFID tags and readers, near field
communication (NFC) devices and embedded sensor and actuator nodes, the IoT has
stepped out of its infancy and is the the next revolutionary technology in
transforming the Internet into a fully integrated Future Internet. As we move
from www (static pages web) to web2 (social networking web) to web3 (ubiquitous
computing web), the need for data-on-demand using sophisticated intuitive
queries increases significantly. This paper presents a cloud centric vision for
worldwide implementation of Internet of Things. The key enabling technologies
and application domains that are likely to drive IoT research in the near
future are discussed. A cloud implementation using Aneka, which is based on
interaction of private and public clouds is presented. We conclude our IoT
vision by expanding on the need for convergence of WSN, the Internet and
distributed computing directed at technological research community.
We propose an evidence theory based anonymity measuring approach for wireless mobile ad-hoc networks. In our approach, an evidence is a measure of the number of detected packets within a given time period. Based on the collected evidence, we can set up basic probability assignments for all packet delivery paths and use evidence theory to quantify the anonymity in the number of bits. Our approach is more general and practical comparing to the traditional Shannon information theory based solutions where the probability assignments are predefined
Source location privacy is an important issue in sensor network monitoring applications. It is difficult to be addressed by traditional security mechanisms, because an external attacker may perform simple traffic analysis to trace back to the event source. Solutions such as flooding or using dummy messages have the drawback of introducing a large amount of message overhead. In this paper, we avoid using network-wide dummy messages by utilizing beacons at the MAC layer. Beacons are sent out regularly, which essentially forms a constant-rate of dummy messages. Using beacons to replace the dummy messages may increase the delivery delay of event information because beacons are only sent out at the predefined beacon interval, but this latency can be controlled. To do this, we propose a cross- layer solution in which the event information is first propagated several hops through a MAC-layer beacon. Then, it is propagated at the routing layer to the destination to avoid further beacon delays. Simulation results show that our cross-layer solutions can maintain low message overhead and high privacy, while controlling delay.
While many protocols for sensor network security provide confidentiality for the content of messages, contextual information usually remains exposed. Such contextual information can be exploited by an adversary to derive sensitive information such as the locations of monitored objects and data sinks in the field. Attacks on these components can significantly undermine any network application. Existing techniques defend the leakage of location information from a limited adversary who can only observe network traffic in a small region. However, a stronger adversary, the global eavesdropper, is realistic and can defeat these existing techniques. This paper first formalizes the location privacy issues in sensor networks under this strong adversary model and computes a lower bound on the communication overhead needed for achieving a given level of location privacy. The paper then proposes two techniques to provide location privacy to monitored objects (source-location privacy)-periodic collection and source simulation-and two techniques to provide location privacy to data sinks (sink-location privacy)-sink simulation and backbone flooding. These techniques provide trade-offs between privacy, communication cost, and latency. Through analysis and simulation, we demonstrate that the proposed techniques are efficient and effective for source and sink-location privacy in sensor networks.
Advances in the areas of embedded systems, computing, and networking are leading to an infrastructure composed of millions of heterogeneous devices. These devices will not simply convey information but process it in transit, connect peer to peer, and form advanced collaborations. This “Internet of Things (IoT)” infrastructure will be strongly integrated with the environment. This paper focuses on researching on the architecture and key technology of Internet of Things. Moreover, the applications of Internet of Things are interpreted in this paper. Especially, the application of IoT in smart grid is emphasized. The work presented here proposes the principal characteristics for an effective integration of the Internet of Things in smart grid.
Anonymous MANET routing relies on techniques such as re-encryption on each hop to hide end-to-end communication relations. However, passive signal detectors and traffic analyzers can still retrieve sensitive information from PHY and MAC layers through statistical traffic analysis. In this paper, we propose a statistical traffic pattern discovery (STPD) system. STPD intends to find out the sources and destinations of captured packets and discover the end-to-end communication relations. The proposed approach does not require analyzers to be actively involved in MANET transmissions or to decrypt the traffic. We present theoretical models as well as extensive simulations to demonstrate our solutions.
The Internet of Things, an emerging global Internet-based technical architecture facilitating the exchange of goods and services in global supply chain networks has an impact on the security and privacy of the involved stakeholders. Measures ensuring the architecture's resilience to attacks, data authentication, access control and client privacy need to be established. An adequate legal framework must take the underlying technology into account and would best be established by an international legislator, which is supplemented by the private sector according to specific needs and thereby becomes easily adjustable. The contents of the respective legislation must encompass the right to information, provisions prohibiting or restricting the use of mechanisms of the Internet of Things, rules on IT-security-legislation, provisions supporting the use of mechanisms of the Internet of Things and the establishment of a task force doing research on the legal challenges of the IoT.
A wireless sensor network (WSN) has important applications such as remote environmental monitoring and target tracking. This has been enabled by the availability, particularly in recent years, of sensors that are smaller, cheaper, and intelligent. These sensors are equipped with wireless interfaces with which they can communicate with one another to form a network. The design of a WSN depends significantly on the application, and it must consider factors such as the environment, the application’s design objectives, cost, hardware, and system constraints. The goal of our survey is to present a comprehensive review of the recent literature since the publication of [I.F. Akyildiz, W. Su, Y. Sankarasubramaniam, E. Cayirci, A survey on sensor networks, IEEE Communications Magazine, 2002]. Following a top-down approach, we give an overview of several new applications and then review the literature on various aspects of WSNs. We classify the problems into three different categories: (1) internal platform and underlying operating system, (2) communication protocol stack, and (3) network services, provisioning, and deployment. We review the major development in these three categories and outline new challenges.
Much of the existing work on wireless sensor networks (WSNs) has focused on addressing the power and computational resource constraints of WSNs by the design of specific routing, MAC, and cross-layer protocols. Recently, there have been heightened privacy concerns over the data collected by and transmitted through WSNs. The wireless transmission required by a WSN, and the self-organizing nature of its architecture, makes privacy protection for WSNs an especially challenging problem. This paper provides a state-of-the-art survey of privacy-preserving techniques for WSNs. In particular, we review two main categories of privacy-preserving techniques for protecting two types of private information, data-oriented and context-oriented privacy, respectively. We also discuss a number of important open challenges for future research. Our hope is that this paper sheds some light on a fruitful direction of future research for privacy preservation in WSNs.
Typical packet traffic in a sensor network reveals pronounced patterns that allow an adversary analyzing packet traffic to deduce the location of a base station. Once discovered, the base station can be destroyed, rendering the entire sensor network inoperative, since a base station is a central point of data collection and hence failure. This paper investigates a suite of decorrelation countermeasures aimed at disguising the location of a base station against traffic analysis attacks. A set of basic countermeasures is described, including hop-by-hop reencryption of the packet to change its appearance, imposition of a uniform packet sending rate, and removal of correlation between a packet’s receipt time and its forwarding time. More sophisticated countermeasures are described that introduce randomness into the path taken by a packet. Packets may also fork into multiple fake paths to further confuse an adversary. A technique is introduced to create multiple random areas of high communication activity called hot spots to deceive an adversary as to the true location of the base station. The effectiveness of these countermeasures against traffic analysis attacks is demonstrated analytically and via simulation using three evaluation criteria: total entropy of the network, total overhead/energy consumed, and the ability to frustrate heuristic-based search techniques to locate a base station.
Nodes in a wireless sensor network (WSN) probe their surroundings and report their findings to a base-station over multi-hop paths. Given the important role of the base-station, an adversary who likes to disrupt the network operation would eagerly look for where the base-station could be and target it with attacks in order to inflict maximum damage. Unfortunately, the continuous flow of traffic towards the base-station creates a pronounced pattern of wireless links that may expose the base-station position and thus make the network more vulnerable.This paper investigates means for boosting the anonymity of the base-station. First, we adapt three models – entropy based model, GSAT test and evidence theory model, to quantify anonymity of the base-station. Then, two novel approaches for boosting the anonymity of the base-station are proposed. One is for the base-station to disguise itself by transmitting some of the data packets it receives with varying intensity. The goal is to create a perception that the base-station node is just another sensor node sending some information and thus confuse the adversary. The second approach is for the base-station to relocate itself to a more concealed position within the network. Relocating the base-station completely scraps/nullifies the adversary’s efforts to track it down and forces him to start his search from scratch. This paper investigates the problem of base-station relocation with respect to when to relocate, where to relocate and how to relocate. These approaches are validated through simulation. Our results show that the proposed measures not only safeguard base-station but also increases the lifetime of the WSN due to uniform energy depletion of sensor nodes.
Wireless sensor networks will be widely deployed in the near future. While much research has focused on making these networks feasible and useful, security has received little attention. We present a suite of security protocols optimized for sensor networks: SPINS. SPINS has two secure building blocks: SNEP and μTESLA. SNEP includes: data confidentiality, two-party data authentication, and evidence of data freshness. μTESLA provides authenticated broadcast for severely resource-constrained environments. We implemented the above protocols, and show that they are practical even on minimal hardware: the performance of the protocol suite easily matches the data rate of our network. Additionally, we demonstrate that the suite can be used for building higher level protocols.
Learn all you need to know about wireless sensor networks!. Protocols and Architectures for Wireless Sensor Networks provides a thorough description of the nuts and bolts of wireless sensor networks. The authors give an overview of the state-of-the-art, putting all the individual solutions into perspective with one and other. Numerous practical examples, case studies and illustrations demonstrate the theory, techniques and results presented. The clear chapter structure, listing learning objectives, outline and summarizing key points, help guide the reader expertly through the material. Protocols and Architectures for Wireless Sensor Networks: Covers architecture and communications protocols in detail with practical implementation examples and case studies. Provides an understanding of mutual relationships and dependencies between different protocols and architectural decisions. Offers an in-depth investigation of relevant protocol mechanisms. Shows which protocols are suitable for which tasks within a wireless sensor network and in which circumstances they perform efficiently. Features an extensive website with the bibliography, PowerPoint slides, additional exercises and worked solutions. This text provides academic researchers, graduate students in computer science, computer engineering, and electrical engineering, as well as practitioners in industry and research engineers with an understanding of the specific design challenges and solutions for wireless sensor networks. Check out www.wiley.com/go/wsn for accompanying course material!. "I am deeply impressed by the book of Karl & Willig. It is by far the most complete source for wireless sensor networks. The book covers almost all topics related to sensor networks, gives an amazing number of references, and, thus, is the perfect source for students, teachers, and researchers. Throughout the book the reader will find high quality text, figures, formulas, comparisons etc. - all you need for a sound basis to start sensor network research."
For sensor networks deployed to monitor and report real events, event source anonymity is an attractive and critical security property, which unfortunately is also very difficult and expensive to achieve. This is not only because adversaries may attack against sensor source privacy through traffic analysis, but also because sensor networks are very limited in resources. As such, a practical tradeoff between security and performance is desirable. In this paper, for the first time we propose the notion of statistically strong source anonymity, under a challenging attack model where a global attacker is able to monitor the traffic in the entire network. We propose a scheme called FitProbRate, which realizes statistically strong source anonymity for sensor networks. We also demonstrate the robustness of our scheme under various statistical tests that might be employed by the attacker to detect real events. Our analysis and simulation results show that our scheme, besides providing source anonymity, can significantly reduce real event reporting latency compared to two baseline schemes.
While many protocols for sensor network security provide confidentiality for the content of messages, contextual information usually remains exposed. Such information can be critical to the mission of the sensor network, such as the location of a target object in a monitoring application, and it is often important to protect this information as well as message content. There have been several recent studies on providing location privacy in sensor networks. However, these existing approaches assume a weak adversary model where the adversary sees only local network traffic. We first argue that a strong adversary model, the global eavesdropper, is often realistic in practice and can defeat existing techniques. We then formalize the location privacy issues under this strong adversary model and show how much communication overhead is needed for achieving a given level of privacy. We also propose two techniques that prevent the leakage of location information: periodic collection and source simulation. Periodic collection provides a high level of location privacy, while source simulation provides trade-offs between privacy, communication cost, and latency. Through analysis and simulation, we demonstrate that the proposed techniques are efficient and effective in protecting location information from the attacker.
Due to the broadcast nature of radio transmissions, communications in mobile ad hoc networks (MANETs) are more susceptible to malicious traffic analysis. In this paper we propose a novel anonymous on-demand routing protocol, termed MASK, to enable anonymous communications thereby thwarting possible traffic analysis attacks. Based on a new cryptographic concept called pairing, we first propose an anonymous neighborhood authentication protocol which allows neighboring nodes to authenticate each other without revealing their identities. Then utilizing the secret pairwise link identifiers and keys established between neighbors during the neighborhood authentication process, MASK fulfills the routing and packet forwarding tasks nicely without disclosing the identities of participating nodes under a rather strong adversarial model. MASK provides the desirable sender and receiver anonymity, as well as the relationship anonymity of the sender and receiver. It is also resistant to a wide range of adversarial attacks. Moreover, MASK preserves the routing efficiency in contrast to previous proposals. Detailed anonymity analysis and simulation studies are carried out to validate and justify the effectiveness of MASK.
We characterize the fundamental limits of localization using signal strength in indoor environments. Signal strength approaches are attractive because they are widely applicable to wireless sensor networks and do not require additional localization hardware. We show that although a broad spectrum of algorithms can trade accuracy for precision, none has a significant advantage in localization performance. We found that using commodity 802.11 technology over a range of algorithms, approaches and environments, one can expect a median localization error of 10 ft and 97th percentile of 30 ft. We present strong evidence that these limitations are fundamental and that they are unlikely to transcend without a fundamentally more complex environmental models or additional localization infrastructure.
Energy efficient communication is a fundamental problem in wireless ad-hoc and sensor networks. In this paper, we explore the feasibility of a distributed beamforming approach to this problem, with a cluster of distributed transmitters emulating a centralized antenna array so as to transmit a common message signal coherently to a distant base station. The potential SNR gains from beamforming are well-known. However, realizing these gains requires synchronization of the individual carrier signals in phase and frequency. In this paper we show that a large fraction of the beamforming gains can be realised even with imperfect synchronization corresponding to phase errors with moderately large variance. We present a master-slave architecture where a designated master transmitter coordinates the synchronization of other (slave) transmitters for beamforming. We observe that the transmitters can achieve distributed beamforming with minimal coordination with the base station using channel reciprocity. Thus, inexpensive local coordination with a master transmitter makes the expensive communication with a distant base station receiver more efficient. However, the duplexing constraints of the wireless channel place a fundamental limitation on the achievable accuracy of synchronization. We present a stochastic analysis that demonstrates the robustness of beamforming gains with imperfect synchronization, and demonstrate a tradeoff between synchronization overhead and beamforming gains. We also present simulation results for the phase errors that validate the analysis
Wireless ad-hoc sensor networks have emerged as an interesting and important research area in the last few years. The applications envisioned for such networks require collaborative execution of a distributed task amongst a large set of sensor nodes. This is realized by exchanging messages that are timestamped using the local clocks on the nodes. Therefore, time synchronization becomes an indispensable piece of infrastructure in such systems. For years, protocols such as NTP have kept the clocks of networked systems in perfect synchrony. However, this new class of networks has a large density of nodes and very limited energy resource at every node; this leads to scalability requirements while limiting the resources that can be used to achieve them. A new approach to time synchronization is needed for sensor networks.
The recent advances in radio and embedded system technologies have enabled the proliferation of wireless microsensor net works. Such wirelessly connected sensors are released in many diverse environments to perform various monitoring tasks. In many such tasks, location awareness is inherently one of the most essential system parameters. It is not only needed to report the origins of events, but also to assist group querying of sensors, routing, and to answer questions on the network coverage. In this paper we present a novel approach to the localization of sensors in an adhoc network. We describe a system called AHLoS (Ad-Hoc Localization System) that enables sensor nodes to discover their locations using a set distributed iterative algorithms. The operation of AHLoS is demonstrated with an accuracy of a few centimeters using our prototype testbed while scalability and performance are studied through simulation.