Passive radio-frequency identification (RFID) communication raises new transmission secrecy protection challenges, since passive tags stored information lack effective information protection mechanisms. Due to constraints of passive tags, such as limited computation and storage capabilities, security solutions based on the physical-layer security (PLS) are promising candidates compared to those based on conventional lightweight cryptography. Unlike existing endeavors on PLS of RFID wireless communication, we consider an RFID system in the presence of a special proactive eavesdropper, which is able to both enhance the information wiretap and interfere with the information detection at the RFID reader simultaneously by broadcasting its own continuous-wave (CW) signal. To defend against proactive eavesdropping attacks, we propose a wiretap-channel-conscious artificial-noise (AN)-aided secure transmission scheme for the RFID reader, which first estimates both legitimate and wiretap channels and then superimposes an AN signal on the CW signal to confuse the proactive eavesdropper. The transmit power and power allocation between the AN signal and the CW signal are optimized to maximize the secrecy rate. Furthermore, we model the attack and defense process between the proactive eavesdropper and the RFID reader as a hierarchical security game and prove it can achieve the equilibrium. The simulation results show the superiority of our proposed scheme in terms of the secrecy rate and the interactions between the RFID reader and the proactive eavesdropper.
Passive radio-frequency identification (RFID) communication raises new transmission secrecy protection challenges, since passive tags stored information lack effective information protection mechanisms. Due to constraints of passive tags, such as limited computation and storage capabilities, security solutions based on the physical-layer security (PLS) are promising candidates compared to those based on conventional lightweight cryptography. Unlike existing endeavors on PLS of RFID wireless communication, we consider an RFID system in the presence of a special proactive eavesdropper, which is able to both enhance the information wiretap and interfere with the information detection at the RFID reader simultaneously by broadcasting its own continuous-wave (CW) signal. To defend against proactive eavesdropping attacks, we propose a wiretap-channel-conscious artificial-noise (AN)-aided secure transmission scheme for the RFID reader, which first estimates both legitimate and wiretap channels and then superimposes an AN signal on the CW signal to confuse the proactive eavesdropper. The transmit power and power allocation between the AN signal and the CW signal are optimized to maximize the secrecy rate. Furthermore, we model the attack and defense process between the proactive eavesdropper and the RFID reader as a hierarchical security game and prove it can achieve the equilibrium. The simulation results show the superiority of our proposed scheme in terms of the secrecy rate and the interactions between the RFID reader and the proactive eavesdropper.
Passive radio frequency identification (RFID) systems raise new transmission secrecy protection challenges against the special proactive eavesdropper, since it is able to both enhance the information wiretap and interfere with the information detection at the RFID reader simultaneously by broadcasting its own continuous wave (CW) signal. To defend against proactive eavesdropping attacks, we propose an artificial noise (AN) aided secure transmission scheme for the RFID reader, which superimposes an AN signal on the CW signal to confuse the proactive eavesdropper. The power allocation between the AN signal and the CW signal are optimized to maximize the secrecy rate. Furthermore, we model the attack and defense process between the proactive eavesdropper and the RFID reader as a hierarchical security game, and prove it can achieve the equilibrium. Simulation results show the superiority of our proposed scheme in terms of the secrecy rate and the interactions between the RFID reader and the proactive eavesdropper.
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.
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.
Proactive eavesdropping is an effective approach to legitimately surveil the suspicious communications. Current studies all considered that physical layer security (PLS) techniques such as the wiretap coding are not applied by the suspicious users (SUs) to protect their communications. Contrary to that, we consider that the wiretap coding in PLS is adopted by the SUs to defend against the proactive eavesdropping from the legitimate monitor over fading channels. Under the fixed power allocation (FPA) and the water-filling power allocation (WFPA) at the SUs, the problem of jamming power allocation at the monitor to maximize the relative eavesdropping rate under the average transmit power constraint is investigated. The optimization problem is solved by two nested optimizations, where the bisection search method is used in the outer optimization, and the Lagrange duality method and the successive convex approximation method are used in the inner optimization. Simulation results confirm the effectiveness of the proposed algorithms compared to various baseline algorithms. It is shown that the proposed algorithm under the WFPA at the SUs outperforms the one under the FPA at the SUs, and the monitor achieves lower relative eavesdropping rate when the SUs adopt a stricter secure transmission scheme.
In this paper, we proposed a scheme that Injects artificial noise from the tag end (IANT) to enhance the physical layer security of the ambient backscatter communication (ABC) system. The difference between the ABC system and the traditional radio frequency identification system is whether it uses the radio frequency (RF) signals in the environment to supply energy and modulation information for passive tags. In the IANT scheme, we select the best tag to communicate with the reader according to the channel quality between tags and reader, and at the same time select another tag to generate artificial noise that affects the receiving effect of the eavesdropper. This paper uses the method of generating noise copies in the reader to reduce the interference of artificial noise on the signal received by the reader. The simulation results show that with the increase in channel quality between tags and reader and the increase in the number of tags, the proposed IANT scheme is significantly superior to the contrast scheme in terms of system achievable secrecy rate, effectively enhancing the physical layer security of the ABC system.
In this paper, we propose an artificial noise-aided tag scheduling (ANTS) scheme in order to enhance physical layer security in ambient backscatter communications (ABCs), which utilize existing radio frequency (RF) signals such as TV, FM radio, Wi-Fi, and so on. In more detail, we first select the best tag based on the channel gain between a tag and a reader and then select another tag for generating artificial noise affecting an eavesdropper. Consequently, we propose a scheduling criterion to choose both information and artificial noise tags. In addition, we apply a successive interference cancellation (SIC) technique at the reader in order to eliminate the interference from the artificial noise tag. The simulation results show that our proposed ANTS scheme can obtain a better secrecy rate as the channel gain between the tag and the receiver increases and the number of tags increases. Moreover, when the number of tags is sufficiently large, the proposed ANTS scheme significantly outperforms the conventional scheme in terms of average secrecy rate.