The necessity for ultra-low-power consumption devices that enable the Internet of Things (IoT) networks to be more energy efficient, leads to considering Ambient Backscatter Communication (AmBC). Such devices exploit ambient radio-frequency signals to communicate and harvest energy. Though, the physical layer key generation (PLKG) scheme that enables AmBC to generate a secret key for data encryption, is vulnerable to injection attacks. Under such a menace, an attacker injects predefined signals and contributes to the PLKG. Thereby, it possesses a part of the generated bits and uses brute force attack to compromise the entire key. Inspired by that, we carefully prove the vulnerability of the existing PLKG approach in AmBC to injection attack. Then, we propose the employment of a smart device that aims at detecting the attack and canceling the malicious signal. Furthermore, we propose a new strategy that enables legitimate devices to utilize the entire received ambient signal for PLKG while exploiting the malicious signal for energy harvesting. Hence, the attacker becomes the victim. Finally, we provide numerical simulations that accentuate the consequence of the menace and the effectiveness of our security method, even though only 80% of the injected signal is removed. Besides, we prove the efficacy of our energy harvesting strategy.
The necessity for ultra-low-power consumption devices that enable the Internet of Things (IoT) networks to be more energy efficient, leads to considering Ambient Backscatter Communication (AmBC). Such devices exploit ambient radio-frequency signals to communicate and harvest energy. Though, the physical layer key generation (PLKG) scheme that enables AmBC to generate a secret key for data encryption, is vulnerable to injection attacks. Under such a menace, an attacker injects predefined signals and contributes to the PLKG. Thereby, it possesses a part of the generated bits and uses brute force attack to compromise the entire key. Inspired by that, we carefully prove the vulnerability of the existing PLKG approach in AmBC to injection attack. Then, we propose the employment of a smart device that aims at detecting the attack and canceling the malicious signal. Furthermore, we propose a new strategy that enables legitimate devices to utilize the entire received ambient signal for PLKG while exploiting the malicious signal for energy harvesting. Hence, the attacker becomes the victim. Finally, we provide numerical simulations that accentuate the consequence of the menace and the effectiveness of our security method, even though only 80% of the injected signal is removed. Besides, we prove the efficacy of our energy harvesting strategy.
Ambient backscatter communication (AmBC), which enables energy harvesting and ultra-low-power communication by utilizing ambient radio frequency (RF) signals, has emerged as a cutting-edge technology to realize numerous Internet of Things (IoT) applications. However, the current literature lacks efficient secret key sharing solutions for resource-limited devices in AmBC systems to protect the backscatter communications, especially for private data transmission. Thus, we propose a novel physical layer key generation scheme between backscatter devices (BDs) by exploiting received superposed ambient signals. Based on the repeated patterns (i.e., cyclic prefix in OFDM symbols) in ambient RF signals, we present a joint transceiver design of BD backscatter waveform and BD receiver to extract the downlink signal and the backscatter signal from the superposed signals. By multiplying the downlink signal and the backscatter signal, we can actually obtain the triangle channel information as a shared random secret source for key generation. Besides, we study the trade-off between the rate of secret key generation and harvested energy by modeling it as a joint optimization problem. Finally, extensive numerical simulations are provided to evaluate the key generation performance, energy harvesting performance, and their trade-offs under various system settings.
Ambient backscatter communication (AmBC) enables ultra-low-power communications by backscattering ambient radio frequency (RF) signals and harvesting energy simultaneously. It has emerged as a cutting-edge technology for supporting a variety of Internet of Things (IoT) applications. However, existing research lacks effective secret key sharing schemes for safeguarding communications between resource-constrained backscatter devices (BDs) in AmBC systems. In this paper, we present, Tri-Channel, a novel physical layer key generation scheme between two BDs by multiplying downlink signals and backscatter signals to obtain the information of a triangle channel as a shared random secret source for key generation. In particular, we analyze the security of our scheme under both passive and active attacks, concretely Eavesdropping Attack (EA), Control Channel Attack (CCA), Signal Manipulative Attack (SMA), and Untrusted RF-Source Attack (URSA). Through theoretical analysis and simulations by comparing with a traditional scheme (named Tradi-Channel), we found that our scheme consistently outperforms the Tradi-Channel under the EA and two active attacks (CCA and SMA). In addition, it shows better security performance under URSA, which is proposed based on the unauthenticated characteristic of BDs in Tri-Channel, even though URSA is more vital than SMA. Concretely, Tri-Channel’s secret key rate (SKR) outperforms Tradi-Channel’s under the above four passive and active attacks. This implies that our scheme is advanced in terms of both security and efficiency of key generation. Numerous extensive simulations further prove our theoretical analysis results.
With the burgeoning internet of things (IoT), securing communication becomes paramount. Traditional cryptography does not meet computational needs and brute-force attacks. This review explores the state-of-the-art physical layer secret key generation (PLKG) that takes advantage of the inherent reciprocity and randomness of wireless channels. We investigate cutting-edge techniques such as feature extraction networks, domain adversarial training, and deep learning-based approaches, evaluating their effects on the security and efficiency of key generation. In addition to these methods, the review addresses real-world challenges such as multi-user scenarios, reconciliation overhead, and inconsistent channel measurement. We believe that improved key generation rates and security can be achieved through the use of millimeter wave technology and full-duplex communication. To strengthen the robustness of key generation, the paper concludes by suggesting future directions, such as incorporating more random sources, such as physiological signals and sensor data. This comprehensive overview offers deep insights into the state-of-the-art and paves the way for reliable communication in ever more complicated IoT settings.
Ambient Power-enabled Internet of Things (AIoT) is expected to be a key technology for future 6G to support green and sustainable development. Developing lightweight security mechanisms to accommodate the extremely low power consumption of AIoT devices is of vital importance. Physical layer key generation (PLKG) is expected to be a promising security technology for AIoT. Considering the widespread application of one-to-many communication paradigm in AIoT systems, in this paper, we propose a physical layer group key generation (PLGKG) scheme to support the secure group communications among multiple AIoT devices. By designing the precoding weight coefficient of the reader, multiple AIoT devices can receive the same key source at the same time, and thus obtain the common group key. The system security is analyzed and the achievable group key rate (GKR) is also derived. Simulation results show that the proposed scheme not only reduces the time overhead of group key generation, but also achieves the lower group key disagreement ratio (GKDR).
Lightweight session key agreement schemes are expected to play a central role in building Internet of things (IoT) security in sixth-generation (6G) networks. A well-established approach deriving from the physical layer is a secret key generation (SKG) from shared randomness (in the form of wireless fading coefficients). However, although practical, SKG schemes have been shown to be vulnerable to active attacks over the initial "advantage distillation" phase, throughout which estimates of the fading coefficients are obtained at the legitimate users. In fact, by injecting carefully designed signals during this phase, a man-in-the-middle (MiM) attack could manipulate and control part of the reconciled bits and thus render SKG vulnerable to brute force attacks. Alternatively, a denial of service attack can be mounted by a reactive jammer. In this paper, we investigate the impact of injection and jamming attacks during the advantage distillation in a multiple-input-multiple-output (MIMO) system. First, we show that a MiM attack can be mounted as long as the attacker has one extra antenna with respect to the legitimate users, and we propose a pilot randomization scheme that allows the legitimate users to successfully reduce the injection attack to a less harmful jamming attack. Secondly, by taking a game-theoretic approach we evaluate the optimal strategies available to the legitimate users in the presence of reactive jammers.
As aspects of our daily lives become more interconnected with the emergence of the Internet of Things (IoT), it is imperative that our devices are reliable and secure from threats. Vulnerabilities of Wi-Fi Protected Access (WPA/WPA2) have been exposed in the past, motivating the use of multiple security techniques, even with the release of WPA3. Physical layer security leverages existing components of communication systems to enable methods of protecting devices that are well-suited for IoT applications. In this work, we provide a low-complexity technique for generating secret keys at the Physical layer to enable improved IoT security. We leverage the existing carrier frequency offset (CFO) and channel estimation components of Orthogonal Frequency Division Multiplexing (OFDM) receivers for an efficient approach. The key generation algorithm we propose focuses on the unique CFO and channel experienced between a pair of desired nodes, and to the best of our understanding, the combination of the features has not been examined previously for the purpose of secret key generation. Our techniques are appropriate for IoT devices, as they do not require extensive processing capabilities and are based on second order statistics. We obtain experimental results using USRP N210 software defined radios and analyze the performance of our methods in post-processing. Our techniques improve the capability of desired nodes to establish matching secret keys, while hindering the threat of an eavesdropper, and are useful for protecting future IoT devices.