56 research outputs found
Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
This paper provides a comprehensive review of the domain of physical layer
security in multiuser wireless networks. The essential premise of
physical-layer security is to enable the exchange of confidential messages over
a wireless medium in the presence of unauthorized eavesdroppers without relying
on higher-layer encryption. This can be achieved primarily in two ways: without
the need for a secret key by intelligently designing transmit coding
strategies, or by exploiting the wireless communication medium to develop
secret keys over public channels. The survey begins with an overview of the
foundations dating back to the pioneering work of Shannon and Wyner on
information-theoretic security. We then describe the evolution of secure
transmission strategies from point-to-point channels to multiple-antenna
systems, followed by generalizations to multiuser broadcast, multiple-access,
interference, and relay networks. Secret-key generation and establishment
protocols based on physical layer mechanisms are subsequently covered.
Approaches for secrecy based on channel coding design are then examined, along
with a description of inter-disciplinary approaches based on game theory and
stochastic geometry. The associated problem of physical-layer message
authentication is also introduced briefly. The survey concludes with
observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with
arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials,
201
Performance Analysis of Secondary Users in Heterogeneous Cognitive Radio Network
Continuous increase in wireless subscriptions and static allocation of wireless frequency bands to the primary users (PUs) are fueling the radio frequency (RF) shortage problem. Cognitive radio network (CRN) is regarded as a solution to this problem as it utilizes the scarce RF in an opportunisticmanner to increase the spectrumefficiency. InCRN, secondary users (SUs) are allowed to access idle frequency bands opportunistically without causing harmful interference to the PUs. In CRN, the SUs determine the presence of PUs through spectrum sensing and access idle bands by means of dynamic spectrum access. Spectrum sensing techniques available in the literature do not consider mobility. One of the main objectives of this thesis is to include mobility of SUs in spectrum sensing. Furthermore, due to the physical characteristics of CRN where licensed RF bands can be dynamically accessed by various unknown wireless devices, security is a growing concern. This thesis also addresses the physical layer security issues in CRN. Performance of spectrum sensing is evaluated based on probability of misdetection and false alarm, and expected overlapping time, and performance of SUs in the presence of attackers is evaluated based on secrecy rates
Cognitive Security Framework For Heterogeneous Sensor Network Using Swarm Intelligence
Rapid development of sensor technology has led to applications ranging from academic to military in a short time span. These tiny sensors are deployed in environments where security for data or hardware cannot be guaranteed. Due to resource constraints, traditional security schemes cannot be directly applied. Unfortunately, due to minimal or no communication security schemes, the data, link and the sensor node can be easily tampered by intruder attacks. This dissertation presents a security framework applied to a sensor network that can be managed by a cohesive sensor manager. A simple framework that can support security based on situation assessment is best suited for chaotic and harsh environments. The objective of this research is designing an evolutionary algorithm with controllable parameters to solve existing and new security threats in a heterogeneous communication network. An in-depth analysis of the different threats and the security measures applied considering the resource constrained network is explored. Any framework works best, if the correlated or orthogonal performance parameters are carefully considered based on system goals and functions. Hence, a trade-off between the different performance parameters based on weights from partially ordered sets is applied to satisfy application specific requirements and security measures. The proposed novel framework controls heterogeneous sensor network requirements,and balance the resources optimally and efficiently while communicating securely using a multi-objection function. In addition, the framework can measure the affect of single or combined denial of service attacks and also predict new attacks under both cooperative and non-cooperative sensor nodes. The cognitive intuition of the framework is evaluated under different simulated real time scenarios such as Health-care monitoring, Emergency Responder, VANET, Biometric security access system, and Battlefield monitoring. The proposed three-tiered Cognitive Security Framework is capable of performing situation assessment and performs the appropriate security measures to maintain reliability and security of the system. The first tier of the proposed framework, a crosslayer cognitive security protocol defends the communication link between nodes during denial-of-Service attacks by re-routing data through secure nodes. The cognitive nature of the protocol balances resources and security making optimal decisions to obtain reachable and reliable solutions. The versatility and robustness of the protocol is justified by the results obtained in simulating health-care and emergency responder applications under Sybil and Wormhole attacks. The protocol considers metrics from each layer of the network model to obtain an optimal and feasible resource efficient solution. In the second tier, the emergent behavior of the protocol is further extended to mine information from the nodes to defend the network against denial-of-service attack using Bayesian models. The jammer attack is considered the most vulnerable attack, and therefore simulated vehicular ad-hoc network is experimented with varied types of jammer. Classification of the jammer under various attack scenarios is formulated to predict the genuineness of the attacks on the sensor nodes using receiver operating characteristics. In addition to detecting the jammer attack, a simple technique of locating the jammer under cooperative nodes is implemented. This feature enables the network in isolating the jammer or the reputation of node is affected, thus removing the malicious node from participating in future routes. Finally, a intrusion detection system using `bait\u27 architecture is analyzed where resources is traded-off for the sake of security due to sensitivity of the application. The architecture strategically enables ant agents to detect and track the intruders threateningthe network. The proposed framework is evaluated based on accuracy and speed of intrusion detection before the network is compromised. This process of detecting the intrusion earlier helps learn future attacks, but also serves as a defense countermeasure. The simulated scenarios of this dissertation show that Cognitive Security Framework isbest suited for both homogeneous and heterogeneous sensor networks
On Myopic Sensing for Multi-Channel Opportunistic Access: Structure, Optimality, and Performance
We consider a multi-channel opportunistic communication system where the
states of these channels evolve as independent and statistically identical
Markov chains (the Gilbert-Elliot channel model). A user chooses one channel to
sense and access in each slot and collects a reward determined by the state of
the chosen channel. The problem is to design a sensing policy for channel
selection to maximize the average reward, which can be formulated as a
multi-arm restless bandit process. In this paper, we study the structure,
optimality, and performance of the myopic sensing policy. We show that the
myopic sensing policy has a simple robust structure that reduces channel
selection to a round-robin procedure and obviates the need for knowing the
channel transition probabilities. The optimality of this simple policy is
established for the two-channel case and conjectured for the general case based
on numerical results. The performance of the myopic sensing policy is analyzed,
which, based on the optimality of myopic sensing, characterizes the maximum
throughput of a multi-channel opportunistic communication system and its
scaling behavior with respect to the number of channels. These results apply to
cognitive radio networks, opportunistic transmission in fading environments,
and resource-constrained jamming and anti-jamming.Comment: To appear in IEEE Transactions on Wireless Communications. This is a
revised versio
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Everlasting Secrecy by Exploiting Eavesdropper\u27s Receiver Non-Idealities
This dissertation focuses on secrecy, which is a primary concern in modern communication. Secrecy has traditionally been obtained by cryptography, which is based on assumptions on current and future computational capabilities of the eavesdropper. However, there are numerous examples of cryptographic schemes being broken that were supposedly secure, often when the signal was recorded by the adversary for later processing. This motivates seeking types of secrecy that are provably everlasting for sensitive applications. The desire for such everlasting security suggests considering information-theoretic approaches, where the eavesdropper cannot extract any information about the secret message from the received signal. However, since the location and channel state information of a passive eavesdropper is generally unknown, it is challenging to know whether the advantage required to achieve information-theoretic security for a given scenario is provided, and thus attempting to obtain information-theoretic security via commonly-envisioned approaches leads to a significant risk in wireless communication.
In this dissertation, we present a new perspective on how to generate the necessary information-theoretic advantage required for secret communication in the wireless environment. The proposed technique does not rely on the channel between the transmitter and the eavesdropper\u27s receiver because we exploit receiver\u27s processing effects for security. In particular, we attack the eavesdropper\u27s analog-to-digital (A/D) converter to generate the advantage required to obtain information-theoretic secrecy, as follows. Based on a key pre-shared between the legitimate nodes that only needs to be kept secret during transmission (and we pessimistically assume it will be handed to the adversary immediately afterward) we insert intentional distortion on the transmitted signal. Since the intended recipient of the signal knows the key and hence the distortion, it can undo the distortion before his/her A/D, whereas the eavesdropper must store the signal in memory and try to compensate for the distortion after the A/D conversion. Since the A/D is necessarily a non-linear component of the receiver, the operations are not necessarily commutative and there is the potential for information-theoretic security. This dissertation studies two practical instantiations of this approach to obtain everlasting secrecy against eavesdroppers with different hardware capabilities. As a first step, the transmitted signal is modulated by two vastly different power levels at the transmitter based on the key. Since the intended recipient knows the key, he/she can undo the power modulation before the A/D, putting the signal in the appropriate range for analog-to-digital conversion. The eavesdropper, on the other hand, must compromise between larger quantization noise and more A/D overflows, and thus will lose information required to recover the message. Hence, information-theoretic security is obtained. We show that this method can provide information-theoretic secrecy even when the eavesdropper has perfect access to the output of the transmitter, and even when the eavesdropper has an A/D that has better quality than the legitimate receiver\u27s A/D. A risk of the power modulation approach is a sophisticated eavesdropper with multiple A/Ds. In our second approach, in order to attack such an eavesdropper, we introduce the idea of adding random jamming (based on the ephemeral key) to the signal. In this case the intended recipient can simply subtract off the jamming signal and its signal will be well-matched to the span of its A/D converter, while the eavesdropper has difficulty because it does not know the key during transmission: if it does not change the span of the A/D, it will lose information due to A/D overflows, and, if it enlarges the span of the A/D to cover all possible received signal values, the width of each quantization level will be increased, and thus the eavesdropper will lose information due to high quantization noise. Hence, the desired advantage for information-theoretic secrecy is obtained. Finally, we study the combination of random jamming and frequency hopping in wideband channels, and show that considering the current fundamental limits of analog-to-digital conversion, this method can provide everlasting secrecy in wireless environments against any eavesdropper
Protecting Secret Key Generation Systems Against Jamming: Energy Harvesting and Channel Hopping Approaches
Jamming attacks represent a critical vulnerability for wireless secret key generation (SKG) systems. In this paper, two counter-jamming approaches are investigated for SKG systems: first, the employment of energy harvesting (EH) at the legitimate nodes to turn part of the jamming power into useful communication power, and, second, the use of channel hopping or power spreading in block fading channels to reduce the impact of jamming. In both cases, the adversarial interaction between the pair of legitimate nodes and the jammer is formulated as a two-player zero-sum game and the Nash and Stackelberg equilibria are characterized analytically and in closed form. In particular, in the case of EH receivers, the existence of a critical transmission power for the legitimate nodes allows the full characterization of the game's equilibria and also enables the complete neutralization of the jammer. In the case of channel hopping versus power spreading techniques, it is shown that the jammer's optimal strategy is always power spreading while the legitimate nodes should only use power spreading in the high signal-to-interference ratio (SIR) regime. In the low SIR regime, when avoiding the jammer's interference becomes critical, channel hopping is optimal for the legitimate nodes. Numerical results demonstrate the efficiency of both counter-jamming measures
์ด๊ธฐ์ข ๋ฌด์ ๋คํธ์ํฌ์์์ ํ๋์ญ ์์คํ ๋ณดํธ ๊ธฐ๋ฒ
ํ์๋
ผ๋ฌธ (๋ฐ์ฌ)-- ์์ธ๋ํ๊ต ๋ํ์ : ์ ๊ธฐยท์ปดํจํฐ๊ณตํ๋ถ, 2013. 8. ๊น์ข
๊ถ.์ต๊ทผ ๋ค์ํ ๋ฌด์ ๋คํธ์ํฌ ๊ธฐ์ ๋ค(์์ดํ์ด, ๋ธ๋ฃจํฌ์ค, ์ง๊ทธ๋น)์ด 2.4GHz ๋์ญ์ ISM ๋ฐด๋์ ๊ณต์กดํจ์ผ๋ก ์ธํ์ฌ ์ด๋ค ๊ฐ์ ์ํธ๊ณต์กด์ด ํฐ ๋ฌธ์ ๋ก ๋ํ๋๊ณ ์๋ค. ํนํ ์ง๊ทธ๋น ๋คํธ์ํฌ๋ ํ์ ํ ๋์ ์ ์ก ํ์๋ก ํต์ ํ๋ ์์ดํ์ด ๋คํธ์ํฌ๊ฐ ๋์ผํ ์ฃผํ์ ๋์ญ์ ์กด์ฌํ ๋ ํต์ ์ด ๋ถ๊ฐ๋ฅํด ์ง ์ ๋์ ์ฌ๊ฐํ ์ฑ๋ฅ ์ ํ๋ฅผ ๊ฒช๊ฒ ๋๋ค. ๋ณธ ๋
ผ๋ฌธ์์๋ ์ง๊ทธ๋น ๋คํธ์ํฌ์ ํต์ ์ ์์ดํ์ด ๋คํธ์ํฌ์ ๊ฐ์ญ์ผ๋ก ๋ถํฐ ๋ณดํธํ ์ ์๋ ์ข์ ๋์ญ ๋ณดํธ ๋ฐฉ๋ฒ(Narrow Band Protection)์ ์ ์ํ๋ค. ์๊ฐ ๊ฐ์ง ๋ณดํธ์๋ ์ข์ ๋์ญ ๋ณดํธ ๋ฐฉ๋ฒ์ ํต์ฌ ๊ธฐ์ ๋ก ์ฌ์ ์ ์ ์๋ PN ์ํ์ค์ ๋ํด ์ํธ ์๊ด ๊ธฐ๋ฒ์ ์ด์ฉํ์ฌ ์ค์ค๋ก ์ง๊ทธ๋น ํจํท์ ๋ฐ๊ฒฌํ ์ ์์ด ์ต์ํ์ ์ค๋ฒํค๋๋ก ์ง๊ทธ๋น ๋คํธ์ํฌ๋ฅผ ๋ณดํธํ ์ ์๋ค. ๋ํ, ์๊ฐ ๊ฐ์ง ๋ณดํธ์๋ ์ ๋ขฐ์ฑ ์๋ ์ํธ ์๊ด ๊ธฐ๋ฒ์ ํตํด ๊ธฐ์กด ๋ฐฉ๋ฒ์์ ๋ฐ์ํ๋ ์ ์ด ํจํท ์์ค๋ก ์ธํ ๋ ๋คํธ์ํฌ์ ์ด์ฉํจ์จ ๊ฐ์๋ฅผ ๋ํญ ์ค์ผ ์ ์๋ค. ๋ง์ง๋ง์ผ๋ก, ์๋งจํฑ์ด ๋ถ์ฌ๋ PN ์ฝ๋๋ถ์ ํตํด ์ ์ ๋ ฅ ๋์์ ์ํํ๋ ์ง๊ทธ๋น ๋คํธ์ํฌ์ ๋ค๋ ํจํท ์ ์ก์ ํจ์จ์ ์ผ๋ก ๊ฐ์งํ์ฌ ์ง๊ทธ๋น ๋คํธ์ํฌ์ ๋์ ์ฒ๋ฆฌ๋์ ์ง์ํด ์ค ์ ์๋ ์ฅ์ ์ด ์๋ค. ์ ์ํ๊ณ ์๋ ์๊ฐ ๊ฐ์ง ๋ณดํธ์๋ ์๋งจํฑ์ด ๋ถ์ฌ๋ PN ์ํ์ค๋ฅผ ์ง๊ทธ๋น ํจํท์ ํ๋ฆฌ์ฐ๋ธ(Preamble) ์์ ์๋ฒ ๋ฉ ํ๋ ๊ธฐ๋ฒ์ ์ฌ์ฉํ๋ค. ์ด๋ ํด๋น ๊ธฐ๋ฒ์ ์ ์ฉํ์ง ์๋ ์ง๊ทธ๋น ๋
ธ๋๋ค์ ๋๊ธฐํ๋ฅผ ๋ฐฉํดํ์ง ์๋๋ค. ์ฆ, ์ข์ ๋์ญ ๋ณดํธ ๋ฐฉ๋ฒ์ ๊ธฐ์กด ์ง๊ทธ๋น ๋คํธ์ํฌ์ ํ์ ํธํ์ฑ(backward compatibility)์ ์ ์งํ๋ฉฐ ๊ธฐ์กด ๋ฐฉ๋ฒ์ ๋นํด ๋จ์ผ ํจํท์ ๋ํด์ 1.77๋ฐฐ ๊ฐ๋ ๋์ ์ฒ๋ฆฌ๋์ ์ ๊ณตํด ์ค ์ ์์ผ๋ฉฐ, ๋ค๋ ํจํท ์ ์ก ๋ณดํธ์ ๋ณดํธํ๋ ํจํท์ ์๊ฐ ์ฆ๊ฐํจ์ ๋ฐ๋ผ ์ ํ์ผ๋ก ์ด๋์ด ์ฆ๊ฐํ๊ฒ ๋๋ค. ๋ํ, ์ค์ USRP/GNURadio ํ๋ซํผ์ ํต์ฌ ๊ธฐ๋ฅ์ ๊ตฌํํ์ฌ ์คํจ์ฑ์ ์
์ฆํ์์ผ๋ฉฐ, ์ํ์ ์ธ ๋ถ์๊ณผ ํ์ฅ๋ NS-2 ์๋ฎฌ๋ ์ด์
์ ํตํด ๋ค์ํ ์๊ฐ์์ ์ํธ๊ณต์กด ๋ฌธ์ ๋ฅผ ํด์ํ๊ณ ์์ด ํฅ ํ ๊ด๋ จ ๋ถ์ผ์ ํฐ ๊ธฐ์ฌ๋ฅผ ํ ์ฐ๊ตฌ์ด๋ค.Recent deployment of various wireless technologies such as Wi-Fi, Bluetooth, and ZigBee in the 2.4GHz ISM band has led to the heterogeneous devices coexistence problem. The coexistence problem is particularly challenging since wireless technologies use different PHY/MAC specifications. This thesis deals with the ZigBee and Wi-Fi coexistence problem where a less capable ZigBee device may often experience unacceptably low throughput due to the interference from a powerful Wi-Fi device.
We propose a novel time reservation scheme called Narrow Band Protection (NBP) that uses a protector to guard ongoing ZigBee transmissions. The NBP protector detects a ZigBee transmission by cross-correlating the ZigBee signals with pre-defined Pseudo-random Noise (PN) sequences. A cross-correlation, designed for apprehending certain patterns in signals, not only reduces the control overhead but also guarantees robustness against collisions. In addition, a ZigBee node can still encode its packet length as a PN sequence such that the protector guards a proper length of channel time. We show the feasibility of NBP by implementing it on the USRP/GNURadio platform. We also evaluate the performance of NBP through mathematical analysis and NS-2 simulations. The results show that NBP enhances the ZigBee throughput by up to 1.77x compared to an existing scheme.1 Introduction
1.1 Background
1.2 Goal and Contribution
1.3 Thesis Organization
2 Related Work
2.1 The Cross-technology Interference Problem
2.2 The Cross-technology Interference Solutions
2.3 Signal Correlation
3 Motivation
3.1 Overview of ZigBee and Wi-Fi
3.2 Collision between ZigBee and Wi-Fi packets
3.3 The Limitation of the Protector Approach
4 A Narrow Band Protection Technique
4.1 Overview
4.2 Cross-correlation with PN Codebook
4.3 Protection Coverage
4.4 Protecting Wireless Sensor Networks
4.5 Security Issues
4.6 Discussions
5 Mathematical Analysis
5.1 Assumptions and Notations
5.2 Collision Probability
5.3 Network Performance
5.4 Multiple Packet Transmissions
6 Performance Evaluation
6.1 USRP Experiments
6.2 NS-2 Simulations
7 Conclusion
BibliographyDocto
Multifunction Radios and Interference Suppression for Enhanced Reliability and Security of Wireless Systems
Wireless connectivity, with its relative ease of over-the-air information sharing, is a key technological enabler that facilitates many of the essential applications, such as satellite navigation, cellular communication, and media broadcasting, that are nowadays taken for granted. However, that relative ease of over-the-air communications has significant drawbacks too. On one hand, the broadcast nature of wireless communications means that one receiver can receive the superposition of multiple transmitted signals. But on the other hand, it means that multiple receivers can receive the same transmitted signal. The former leads to congestion and concerns about reliability because of the limited nature of the electromagnetic spectrum and the vulnerability to interference. The latter means that wirelessly transmitted information is inherently insecure.
This thesis aims to provide insights and means for improving physical layer reliability and security of wireless communications by, in a sense, combining the two aspects above through simultaneous and same frequency transmit and receive operation. This is so as to ultimately increase the safety of environments where wireless devices function or where malicious wirelessly operated devices (e.g., remote-controlled drones) potentially raise safety concerns. Specifically, two closely related research directions are pursued. Firstly, taking advantage of in-band full-duplex (IBFD) radio technology to benefit the reliability and security of wireless communications in the form of multifunction IBFD radios. Secondly, extending the self-interference cancellation (SIC) capabilities of IBFD radios to multiradio platforms to take advantage of these same concepts on a wider scale.
Within the first research direction, a theoretical analysis framework is developed and then used to comprehensively study the benefits and drawbacks of simultaneously combining signals detection and jamming on the same frequency within a single platform. Also, a practical prototype capable of such operation is implemented and its performance analyzed based on actual measurements. The theoretical and experimental analysis altogether give a concrete understanding of the quantitative benefits of simultaneous same-frequency operations over carrying out the operations in an alternating manner. Simultaneously detecting and jamming signals specifically is shown to somewhat increase the effective range of a smart jammer compared to intermittent detection and jamming, increasing its reliability.
Within the second research direction, two interference mitigation methods are proposed that extend the SIC capabilities from single platform IBFD radios to those not physically connected. Such separation brings additional challenges in modeling the interference compared to the SIC problem, which the proposed methods address. These methods then allow multiple radios to intentionally generate and use interference for controlling access to the electromagnetic spectrum. Practical measurement results demonstrate that this effectively allows the use of cooperative jamming to prevent unauthorized nodes from processing any signals of interest, while authorized nodes can use interference mitigation to still access the same signals. This in turn provides security at the physical layer of wireless communications
Protecting Secret Key Generation Systems Against Jamming: Energy Harvesting and Channel Hopping Approaches
Jamming attacks represent a critical vulnerability for wireless secret key generation (SKG) systems. In this paper, two counter-jamming approaches are investigated for SKG systems: first, the employment of energy harvesting (EH) at the legitimate nodes to turn part of the jamming power into useful communication power, and, second, the use of channel hopping or power spreading in block fading channels to reduce the impact of jamming. In both cases, the adversarial interaction between the pair of legitimate nodes and the jammer is formulated as a two-player zero-sum game and the Nash and Stackelberg equilibria are characterized analytically and in closed form. In particular, in the case of EH receivers, the existence of a critical transmission power for the legitimate nodes allows the full characterization of the game's equilibria and also enables the complete neutralization of the jammer. In the case of channel hopping versus power spreading techniques, it is shown that the jammer's optimal strategy is always power spreading while the legitimate nodes should only use power spreading in the high signal-to-interference ratio (SIR) regime. In the low SIR regime, when avoiding the jammer's interference becomes critical, channel hopping is optimal for the legitimate nodes. Numerical results demonstrate the efficiency of both counter-jamming measures
Narrowband Interference Detection via Deep Learning
Due to the increased usage of spectrum caused by the exponential growth of
wireless devices, detecting and avoiding interference has become an
increasingly relevant problem to ensure uninterrupted wireless communications.
In this paper, we focus our interest on detecting narrowband interference
caused by signals that despite occupying a small portion of the spectrum only
can cause significant harm to wireless systems, for example, in the case of
interference with pilots and other signals that are used to equalize the effect
of the channel or attain synchronization. Due to the small sizes of these
signals, detection can be difficult due to their low energy footprint, while
greatly impacting (or denying completely in some cases) network communications.
We present a novel narrowband interference detection solution that utilizes
convolutional neural networks (CNNs) to detect and locate these signals with
high accuracy. To demonstrate the effectiveness of our solution, we have built
a prototype that has been tested and validated on a real-world over-the-air
large-scale wireless testbed. Our experimental results show that our solution
is capable of detecting narrowband jamming attacks with an accuracy of up to
99%. Moreover, it is also able to detect multiple attacks affecting several
frequencies at the same time even in the case of previously unseen attack
patterns. Not only can our solution achieve a detection accuracy between 92%
and 99%, but it does so by only adding an inference latency of 0.093ms.Comment: 6 pages, 10 figures, 1 table. ICC 2023 - IEEE International
Conference on Communications, Rome, Italy, May 202
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