The deployment of RFID technology in various applications is delayed due to the increased concerns over possible security breaches, especially in healthcare applications. For medical devices and applications, RFID and IoT technologies can improve the wellbeing of patients and reduce errors at hospitals, but the deployment of RFID is obstructed by multiple barriers including the security concerns. Previous research and studies have proved that traditional cryptography methods cannot be applied on RFID, due to the limited computational, storage and power resources in RFID tags and readers. These constraints emerged the novel idea of exploiting the characteristics of the physical layer to achieve information secrecy in RFID systems. In this thesis, two novel key-less physical layer based secrecy approaches have been developed and analyzed. In first approach a combined beamsteering and injected noise scheme is proposed, where beamsteering is exploited at the tag and the noise injection is exploited at the reader. The results show that this novel approach outperforms previous developed security scheme for RFID. Another novel approach is developed by implementing directional modulation (DM) techniques at the RFID reader while maintaining the simplicity of the tag’s circuity and processing capabilities.
The deployment of RFID technology in various applications is delayed due to the increased concerns over possible security breaches, especially in healthcare applications. For medical devices and applications, RFID and IoT technologies can improve the wellbeing of patients and reduce errors at hospitals, but the deployment of RFID is obstructed by multiple barriers including the security concerns. Previous research and studies have proved that traditional cryptography methods cannot be applied on RFID, due to the limited computational, storage and power resources in RFID tags and readers. These constraints emerged the novel idea of exploiting the characteristics of the physical layer to achieve information secrecy in RFID systems. In this thesis, two novel key-less physical layer based secrecy approaches have been developed and analyzed. In first approach a combined beamsteering and injected noise scheme is proposed, where beamsteering is exploited at the tag and the noise injection is exploited at the reader. The results show that this novel approach outperforms previous developed security scheme for RFID. Another novel approach is developed by implementing directional modulation (DM) techniques at the RFID reader while maintaining the simplicity of the tag’s circuity and processing capabilities.
Backscatter wireless communication lies at the heart of many practical low-cost, low-power, distributed passive sensing systems. The inherent cost restrictions coupled with the modest computational and storage capabilities of passive sensors, such as RFID tags, render the adoption of classical security techniques challenging; which motivates the introduction of physical layer security approaches. Despite their promising potential, little has been done to study the prospective benefits of such physical layer techniques in backscatter systems. In this paper, the physical layer security of wireless backscatter systems is studied and analyzed. First, the secrecy rate of a basic single-reader, single-tag model is studied. Then, the unique features of the backscatter channel are exploited to maximize this secrecy rate. In particular, the proposed approach allows a backscatter system's reader to inject a noise-like signal, added to the conventional continuous wave signal, in order to interfere with an eavesdropper's reception of the tag's information signal. The benefits of this approach are studied for a variety of scenarios while assessing the impact of key factors, such as antenna gains and location of the eavesdropper, on the overall secrecy of the backscatter transmission. Numerical results corroborate our analytical insights and show that, if properly deployed, the injection of artificial noise yields significant performance gains in terms of improving the secrecy of backscatter wireless transmission.
Securing radio frequency identification (RFID) systems against malicious attacks such as eavesdropping is a highly challenging task due to the resource constrained nature of such systems. In fact, the modest computational and storage capabilities of RFID tags makes it impossible to adopt classical cryptographic techniques. While existing work has mostly focused on lightweight cryptographic techniques, in this paper, the first analysis on the adoption of physical layer security techniques in an RFID system is presented. First, the secrecy rate of ultra high frequency (UHF) RFID backscatter systems is characterized. Then, a novel approach is proposed for maximizing this secrecy rate by exploiting the nature and features of the RFID backscatter channel. To explore these features, the proposed approach allows the RFID readers to append artificial noise signals to their continuous wave (CW) signals which then propagate via the backscatter channel hence inducing interference at the eavesdroppers. For enabling the readers to optimally allocate power between their CW signals and artificial noise, a noncooperative game is formulated using which the readers can decide on their optimal power allocations so as to maximize their overall secrecy rates, given the ensuing inter-reader interference. For solving this game, a best response algorithm is proposed using which the readers can reach a Nash equilibrium. Simulation results show that the proposed approach yields significant performance gains, in terms of the average secrecy rate per RFID reader, of at least 17% relative to the classical RFID operation.
Traditionally, spread-spectrum systems have been employed to provide low probability-of-intercept (LPI) and low probability-of-detection (LPD) performances at the physical layer, but the messages transmitted over such a system are still encrypted with a powerful cipher to protect their secrecy. Our challenge is to find a solution to provide an additional level of security at the physical layer so that simple systems such as RFID tags with limited resources can be secure without using standard encryption. It has recently been suggested that the cryptographic security of the system can be enhanced by exploiting physical properties of UWB signals. With an eavesdropper observing the communications over multipath channels between two legitimate partners sharing a secret key of a limited length, we consider both coherent and reference-based UWB schemes to enhance security. The security of the legitimate nodes is achieved by signal attributes based on the secret key, conferring an advantage over the adversary. We propose UWB signaling schemes to improve physical layer security when the transmission is intended for coherent reception and TR reception. Among possible improvements, we consider removing the frame structure of the UWB coherent signaling scheme, resulting in pulses that can be located anywhere in the symbol period. Our proposed signaling schemes could potentially suggest a solution for applications relying on conventional cryptography, especially for low-data rate RFID systems.
The backscatter communication system has tremendous potential in commercial applications, still very less work has been done to study the benefits of it. Backscatter communication system is the backbone of many low cost and low power distributed wireless systems. The data transmission between various nodes in wireless communication system always comes with the risk of third party interception. This leads to privacy and security breaches of the information. In this paper, physical layer security of backscatter wireless system for multiple eavesdropper, single tag, and single reader case is studied. Unique characteristics of the channel are used to provide security to signal transmission. In order to degrade the reception of the signal by eavesdropper, a noise injection scheme is proposed. The advantages of this approach are discussed for various cases while evaluating the impact of the key factors like antenna gain and location of the eavesdropper on the secrecy of the transmission. Analytical results indicate that if properly employed, the noise injection scheme improves the performance of backscatter wireless system.
Wireless communications are naturally exposed to important security risks due to their broadcast nature. In contrast with wired communications, no physical medium is isolating the transmission surroundings to a specific path. Traditional methods to reach the goals of communications security rely on algorithms at protocol stack level, which are based on mathematically derived cryptographic protocols. With the tremendous proliferation of wireless devices, and the increase in computational power available for decryption, traditional cryptographic measures may be compromised. To protect communications at the lowest level, physical layer (PHY) security methods have been proposed recently. These techniques aim to ensure secure communications by exploiting the unique characteristics of the physical medium between communicating nodes, effectively reducing the decryption capabilities of an eavesdropper to intercept transmissions. This thesis explains within a general framework the most important PHY layer security schemes. First we explore approaches which utilize the knowledge of the unique channel between communicating nodes to distort a transmitted signal with various kinds of randomizations, in such a way that the intended receivers are unaffected by the distortion, but any other observer will be exposed to it. These techniques, however, introduce several trade-offs between transmission resources and the effectiveness in achieving secrecy. Of particular interest for this investigation is a class of methods which can be referred to as "security enhancing techniques", in which minimal priors about the potential eavesdroppers locations and capabilities are assumed. In this thesis, a wave-based approach to the communication secrecy problem is introduced. An interesting perspective is provided by studying the relation between electromagnetic theory and information theory, the so-called electromagnetic information theory. This allows to properly identify the unavoidable limitations imposed by the laws of electromagnetics to our ability to communicate securely. The proposed model can be extended to the analysis of different signal distortion methodologies and different channel conditions. The resulting approach is highly relevant to the study of PHY layer security methods since it is physically fundamental as well as architecture independent, which leads to a consolidating point of view of the secrecy problem. In addition, the thesis presents computer simulation results which shed insight on the security possibilities and limitations of three different security scenarios, which are termed MISO (multiple-input, single-output) (with single eavesdropper), MISOME (multiple-input, single-output, multiple eavesdropper), and MIMOME (multiple-input, multiple-output, multiple-eavesdropper).
Radio Frequency Identification (RFID) is a prominent technology within the Internet of Things (IoT) ecosystem, offering efficient and reliable object identification in various domains, including business, healthcare, and manufacturing. The security of RFID systems is of paramount importance, and recent authentication protocols have been developed to address these security concerns. In this survey paper, we explore and evaluate the latest authentication protocols designed to enhance security in RFID communications, primarily concentrating on the interaction between RFID readers and tags. We critically assess contemporary lightweight RFID authentication protocols, considering aspects such as security requirements, computational efficiency, and resilience against potential attacks. However, with the advent of quantum computing, these protocols are under scrutiny for their vulnerability. As a result, we emphasize the need for researchers to shift their focus toward post-quantum cryptography solutions to bolster the security of RFID systems. This paper serves as a comprehensive overview of recent developments in RFID authentication, shedding light on the pressing need for quantum-resistant security measures in this field.