Biblio

Artificial Intelligence (AI) technology is developing rapidly, permeating every aspect of human life. Although the integration between AI and communication contributes to the flourishing development of wireless communication, it induces severer security problems. As a supplement to the upper-layer cryptography protocol, physical layer security has become an intriguing technology to ensure the security of wireless communication systems. However, most of the current physical layer security research does not consider the intelligence and mobility of collusive eavesdroppers. In this paper, we consider a MIMO system model with a friendly intelligent jammer against multiple collusive intelligent eavesdroppers, and zero-sum game is exploited to formulate the confrontation of them. The Nash equilibrium is derived by convex optimization and alternative optimization in the free-space scenario of a single user system. We propose a zero-sum game deep learning algorithm (ZGDL) for general situations to solve non-convex game problems. In terms of the effectiveness, simulations are conducted to confirm that the proposed algorithm can obtain the Nash equilibrium.

This paper assesses the impact on the performance that information-theoretic physical layer security (IT-PLS) introduces when integrated into a 5G New Radio (NR) system. For this, we implement a wiretap code for IT-PLS based on a modular coding scheme that uses a universal-hash function in its security layer. The main advantage of this approach lies in its flexible integration into the lower layers of the 5G NR protocol stack without affecting the communication's reliability. Specifically, we use IT-PLS to secure the transmission of downlink control information by integrating an extra pre-coding security layer as part of the physical downlink control channel (PDCCH) procedures, thus not requiring any change of the 3GPP 38 series standard. We conduct experiments using a real-time open-source 5G NR standalone implementation and use software-defined radios for over-the-air transmissions in a controlled laboratory environment. The overhead added by IT-PLS is determined in terms of the latency introduced into the system, which is measured at the physical layer for an end-to-end (E2E) connection between the gNB and the user equipment.

Physical layer (PHY) security in decode-and-forward (DF) relay systems is discussed. Based on the types of wiretap links, the secrecy performance of three typical secure DF relay models is analyzed. Different from conventional works in this field, rigorous derivations of the secrecy channel capacity are provided from an information-theoretic perspective. Meanwhile, closed-form expressions are derived to characterize the secrecy outage probability (SOP). For the sake of unveiling more system insights, asymptotic analyses are performed on the SOP for a sufficiently large signal-to-noise ratio (SNR). The analytical results are validated by computer simulations and are in excellent agreement.

Nowadays, improving the reliability and security of the transmitted data has gained more attention with the increase in emerging power-limited and lightweight communication devices. Also, the transmission needs to meet specific latency requirements. Combining data encryption and encoding in one physical layer block has been exploited to study the effect on security and latency over traditional sequential data transmission. Some of the current works target secure error-correcting codes that may be candidates for post-quantum computing. However, modifying the popularly used channel coding techniques to guarantee secrecy and maintain the same error performance and complexity at the decoder is challenging since the structure of the channel coding blocks is altered which results in less optimal decoding performance. Also, the redundancy nature of the error-correcting codes complicates the encryption method. In this paper, we briefly review the proposed security schemes on Turbo codes. Then, we propose a secure turbo code design and compare it with the relevant security schemes in the literature. We show that the proposed method is more secure without adding complexity.

This paper investigates the physical layer security of a cognitive radio (CR) non-orthogonal multiple-access (NOMA) network supported by an intelligent reflecting surface (IRS). In a CR network, a secondary base station (BS) serves a couple of users, i.e., near and far users, via NOMA transmission under eavesdropping from a malicious attacker. It is assumed that the direct transmission link from the BS and far user is absent due to obstacles. Thus, an IRS is utilized to support far user communication, however, the communication links between the IRS and near/primary users are neglected because of heavy attenuation. The exact secrecy outage probability (SOP) for the near user and approximate SOP for the far user are then derived in closed-form by using the Gauss-Chebyshev approach. The accuracy of the derived analytical SOP is then verified through Monte Carlo simulations. The simulation results also provide useful insights on the impacts of the number of IRS reflecting elements and limited interference temperature on the system SOP.

In this paper, we studies secure wireless transmission using polar codes which based on self-coupling encryption for relay-wiretap channel. The coding scheme proposed in this paper divide the confidential message into two parts, one part used to generate key through a specific extension method, and then use key to perform coupling encryption processing on another part of the confidential message to obtain the ciphertext. The ciphertext is transmitted in the split-channels which are good for relay node, legitimate receiver and eavesdropper at the same time. Legitimate receiver can restore key with the assistance of relay node, and then uses the joint successive cancellation decoding algorithm to restore confidential message. Even if eavesdropper can correctly decode the ciphertext, he still cannot restore the confidential message due to the lack of key. Simulation results show that compared with the previous work, our coding scheme can increase the average code rate to some extent on the premise of ensuring the reliability and security of transmission.

The high maneuverability of the unmanned aerial vehicle (UAV), facilitating fast and flexible deployment of communication infrastructures, brings potentially valuable opportunities to the future wireless communication industry. Nevertheless, UAV communication networks are faced with severe security challenges since air to ground (A2G) communications are more vulnerable to eavesdropping attacks than terrestrial communications. To solve the problem, we propose a coding scheme that hierarchically utilizes polar codes in order to address channel multi-state variation for UAV wiretap channels, without the instantaneous channel state information (CSI) known at the transmitter. The theoretical analysis and simulation results show that the scheme achieves the security capacity of the channel and meets the conditions of reliability and security.

Blind identification of channel codes is crucial in intelligent communication and non-cooperative signal processing, and it plays a significant role in wireless physical layer security, information interception, and information confrontation. Previous researches show a high computation complexity by manual feature extractions, in addition, problems of indisposed accuracy and poor robustness are to be resolved in a low signal-to-noise ratio (SNR). For solving these difficulties, based on deep residual shrinkage network (DRSN), this paper proposes a novel recognizer by deep learning technologies to blindly distinguish the type and the parameter of channel codes without any prior knowledge or channel state, furthermore, feature extractions by the neural network from codewords can avoid intricate calculations. We evaluated the performance of this recognizer in AWGN, single-path fading, and multi-path fading channels, the results of the experiments showed that the method we proposed worked well. It could achieve over 85 % of recognition accuracy for channel codes in AWGN channels when SNR is not lower than 4dB, and provide an improvement of more than 5% over the previous research in recognition accuracy, which proves the validation of the proposed method.

Spreading codes are the core of the spread spectrum transmission. In this paper, a novel channel-dependent code allocation procedure for enhancing security in multi-carrier code division multiple access (MC-CDMA) system is proposed and investigated over frequency-selective fading. The objective of the proposed technique is to assign the codes to every subcarrier of active/legitimate receivers (Rxs) based on their channel frequency response (CFR). By that, we ensure security for legitimate Rxs against eavesdropping while preserving mutual confidentiality between the legitimate Rxs themselves. To do so, two assigning modes; fixed assigning mode (FAM) and adaptive assigning mode (AAM), are exploited. The effect of the channel estimation error and the number of legitimate Rxs on the bit error rate (BER) performance is studied. The presented simulations show that AAM provides better security with a complexity trade-off compared to FAM. While the latter is more robust against the imperfection of channel estimation.

Physical layer secret key exploits the random but reciprocal channel features between legitimate users to encrypt their data against fiber-tapping. We propose a novel tapping-based eavesdropper scheme, leveraging its tapped signals from legitimate users to reconstruct their common features and the secret key.

This paper presents a physically-secure wireless communication system utilizing orbital angular momentum (OAM) waves at 0.31THz. A trustworthy key distribution mechanism for symmetric key cryptography is proposed by exploiting random hopping among the orthogonal OAM-wave modes and phases. Keccak-f[400] based pseudorandom number generator provides randomness to phase distribution of OAM-wave modes for additional security. We assess the security vulnerabilities of using OAM modulation in a THz communication system under various physical-layer threat models as well as analyze the effectiveness of these threat models for varying attacker complexity levels under different conditions.

Using multi-UAV systems to accomplish both civil and military missions is becoming a popular trend. With the development of software and hardware technologies, Unmanned aerial vehicles (UAVs) are now able to operate autonomously at edge. However, the remote control of manned systems, e.g., ground control station (GCS), remains essential to mission success, and the system's control and non-payload communication (CNPC) are facing severe cyber threats caused by smart attacks. To avoid hijacking, in this paper, we propose a secure mechanism that reduces such security risks for multi-UAV systems. We introduce friendly jamming from UAVs to block eavesdropping on the remote control channel. The trade-off between security and energy consumption is optimized by three approaches designed for UAV and GCS under algorithms of different complexities. Numerical results show the approach efficiency under different mission conditions and security demands, and demonstrate the features of the proposed mechanism for various scenarios.

MIMO system makes full use of the space dimension, in the era of increasingly tense spectrum resources, which greatly improves the spectrum efficiency and is one of the future communication support technologies. At the same time, considering the high cost of direct communication between the two parties in a long distance, the relay communication mode has been paid more and more attention. In relay communication network, each node connected by relay has different security levels. In order to forward the information of all nodes, the relay node has the lowest security permission level. Therefore, it is meaningful to study the physical layer security problem in MIMO two-way relay system with relay as the eavesdropper. In view of the above situation, this paper proposes the physical layer security model of MIMO two-way relay cooperative communication network, designs a communication matching grouping algorithm with low complexity and a two-step carrier allocation optimization algorithm, which improves the total security capacity of the system. At the same time, theoretical analysis and simulation verify the effectiveness of the proposed algorithm.

Vehicular networks are vulnerable to large scale attacks. Blockchain, implemented upon application layer, is recommended as one of the effective security and privacy solutions for vehicular networks. However, due to an increasing complexity of connected nodes, heterogeneous environment and rising threats, a robust security solution across multiple layers is required. Motivated by the Physical Layer Security (PLS) which utilizes physical layer characteristics such as channel fading to ensure reliable and confidential transmission, in this paper we analyze the impact of PLS on a blockchain-enabled vehicular network with two types of physical layer attacks, i.e., jamming and eavesdropping. Throughout the analysis, a Full Duplex Non-Orthogonal Multiple Access (FD-NOMA) based vehicle-to-everything (V2X) is considered to reduce interference caused by jamming and meet 5G communication requirements. Simulation results show enhanced goodput of a blockckchain enabled vehicular network integrated with PLS as compared to the same solution without PLS.

In this short position paper, we discuss several potential security concerns that can be found at the physical layer of 6th-generation (6G) cellular networks. Discussion on 6G cellular networks is still at its early stage and thus several candidate radio technologies have been proposed but no single technology has yet been finally selected for 6G systems. Among several radio technologies, we focus on three promising ones for 6G physical-layer technologies: reconfigurable intelligent surface (RIS), Open-RAN (O-RAN), and full-duplex radios. We hope this position paper will spark more active discussion on the security concerns in these new radio technologies.

A new type of time modulated metamaterial (MTM) antenna array transmitter capable of realizing 2D directional modulation (DM) for physical layer (PHY) security is presented in this work. The proposed 2D DM MTM antenna array is formed by a time modulated corporate feed network loaded with composite right/left-handed (CRLH) leaky wave antennas (LWAs). By properly designing the on-off states of the switch for each antenna feeding branch as well as harnessing the frequency scanning characteristics of CRLH L WAs, 2D DM can be realized to form a PHY secured transmission link in the 2D space. Experimental results demonstrate the bit-error-rate (BER) is low only at a specific 2D angle for the orthogonal frequency-division multiplexing (OFDM) wireless data links.

Security is of vital importance in wireless industrial communication systems. When spoofing attacking has occurred, leading to economic losses or even safety accidents. So as to address the concern, existing approaches mainly rely on traditional cryptographic algorithms. However, these methods cannot meet the needs of short delay and lightweight. In this paper, we propose a CSI-based PHY-layer security authentication scheme to detect spoofing detection. The main idea takes advantage of the uncorrelated nature of wireless channels to the identification of spoofing nodes in the physical layer. We demonstrate a MIMO-OFDM based spoofing detection prototype in industrial environments. Firstly, utilizing Universal Software Radio Peripheral (USRPs) to establish MIMO-OFDM communication systems is presented. Secondly, our proposed security scheme of CSI-based PHY-layer authentication is demonstrated. Finally, the effectiveness of the proposed approach has been verified via attack experiments.

Physical Layer Security (PLS) is used to accomplish perfect secure communication between intended network nodes, while the eavesdropper gets zero information. In this paper, a smart antenna technology i.e., Massive multiple-input-multiple-output (mMIMO) and Non-Orthogonal Multiple Access (NOMA) technology is being used to enhance the secrecy performance of a 5G communication network. Small scale Rayleigh fading channels, as well as large scale pathway loss, have to be taken into consideration. An eavesdropper with multiple antennas, an amplify-and-forward (AF) relay with multi antenna has been proposed. Spider Monkey Algorithm (SMO) is used in adding Artificial Noise (AN) for refining secrecy rate. The findings revealed that the suggested technique improves the security and the quality of Wireless communication.

Wireless security and privacy is gaining a significant interest due to the burgeoning growth of communication devices across the electromagnetic spectrum. In this article, we introduce the concept of the space-time modulated millimeter-wave wireless links enabling physical layer security in highspeed communication links. Such an approach does not require cryptographic key exchanges and enables security in a seamless fashion with no overhead on latency. We show both the design and implementation of such a secure system using custom integrated chips at 71-76 GHz with off-chip packaged antenna array. We also demonstrate the security metric of such a system and analyze the efficacy through distributed eavesdropper attack.

With the continuous development of the Internet, artificial intelligence, 5G and other technologies, various issues have started to receive attention, among which the network security issue is now one of the key research directions for relevant research scholars at home and abroad. This paper researches on the basis of traditional Internet technology to establish a security identification system on top of the network physical layer of the Internet, which can effectively identify some security problems on top of the network infrastructure equipment and solve the identified security problems on the physical layer. This experiment is to develop a security identification system, research and development in the network physical level of the Internet, compared with the traditional development of the relevant security identification system in the network layer, the development in the physical layer, can be based on the physical origin of the protection, from the root to solve part of the network security problems, can effectively carry out the identification and solution of network security problems. The experimental results show that the security identification system can identify some basic network security problems very effectively, and the system is developed based on the physical layer of the Internet network, and the protection is carried out from the physical device, and the retransmission symbol error rates of CQ-PNC algorithm and ML algorithm in the experiment are 110 and 102, respectively. The latter has a lower error rate and better protection.

Unmanned Aerial Vehicles (UAVs) are drawing enormous attention in both commercial and military applications to facilitate dynamic wireless communications and deliver seamless connectivity due to their flexible deployment, inherent line-of-sight (LOS) air-to-ground (A2G) channels, and high mobility. These advantages, however, render UAV-enabled wireless communication systems susceptible to eavesdropping attempts. Hence, there is a strong need to protect the wireless channel through which most of the UAV-enabled applications share data with each other. There exist various error correction techniques such as Low Density Parity Check (LDPC), polar codes that provide safe and reliable data transmission by exploiting the physical layer but require high transmission power. Also, the security gap achieved by these error-correction techniques must be reduced to improve the security level. In this paper, we present deep learning (DL) enabled punctured LDPC codes to provide secure and reliable transmission of data for UAVs through the Additive White Gaussian Noise (AWGN) channel irrespective of the computational power and channel state information (CSI) of the Eavesdropper. Numerical result analysis shows that the proposed scheme reduces the Bit Error Rate (BER) at Bob effectively as compared to Eve and the Signal to Noise Ratio (SNR) per bit value of 3.5 dB is achieved at the maximum threshold value of BER. Also, the security gap is reduced by 47.22 % as compared to conventional LDPC codes.

Physical layer security is an emerging security area to tackle wireless security communications issues and complement conventional encryption-based techniques. Thus, we propose a novel scheme based on swarm intelligence optimization technique and a deep neural network (DNN) for maximizing the secrecy energy efficiency (SEE) in a cooperative relaying underlay cognitive radio- and non-orthogonal multiple access (NOMA) system with a non-linear energy harvesting user which is exposed to multiple eavesdroppers. Satisfactorily, simulation results show that the proposed particle swarm optimization (PSO)-DNN framework achieves close performance to that of the optimal solutions, with a meaningful reduction in computation complexity.

To achieve secure uplink communication from smartphones’ screen to a telephoto camera at a long distance of 3.5 meters, we demonstrate that low-luminance space division multiplexing screen is effective in enhancement of the physical layer security. First, a numerical model shows that the spatial inter-symbol interference caused by space division multiplexing prevents eavesdropping from a wide angle by the camera. Second, wide-angle characteristics of the symbol error rate and the pixel value distribution are measured to verify the numerical analysis. We experimentally evaluate the difference in the performances from a wide angle depending on the screen luminance and color. We also evaluate the performances at a long distance in front of the screen and a short distance from a wider angle.

Visible light communication (VLC) is an important alternative and/or complementary technology for next generation indoor wireless broadband communication systems. In order to ensure data security for VLC in public areas, many studies in literature consider physical layer security (PLS). These studies generally neglect the reflections in the VLC channel and assume no inter symbol interference (ISI). However, increasing the data transmission rate causes ISI. In addition, even if the power of the reflections is small compared to the line of sight (LoS) components, it can affect the secrecy rate in a typical indoor VLC system. In this study, we investigate the effects of ISI and reflected channel components on secrecy rate in multiple-input single-output (MISO) VLC scenario utilized null-steering (NS) and artificial noise (AN) PLS techniques.

Visible light communication (VLC) is a short-range wireless optical communication that can transmit data by switching lighting elements at high speeds in indoor areas. In common areas, VLC can provide data security at every layer of communication by using physical layer security (PLS) techniques as well as existing cryptography-based techniques. In the literature, PLS techniques have generally been studied for monochrome VLC systems, and multicolor VLC studies are quite limited. In this study, to the best of authors’ knowledge, null steering (NS) and artificial noise (AN), which are widely used PLS methods, have been applied to multi-colored LED-based VLC systems for the first time in the literature and the achievable secrecy rate has been calculated.