Physical Layer Security Enhancement Research Articles

Chaotic discrete Fresnel transform for secure OFDM-PONs

A chaotic discrete Fresnel transform (DFnT) precoding scheme is proposed for physical-layer security enhancement in orthogonal frequency division multiplexing passive optical networks (OFDM-PONs). A multi-fold OFDM data encryption is applied in terms of the chaotic scale factor, and chaotic row/column permutations in the DFnT matrix, and the chaos sensitivity creates a huge key space of 10138. The peak-to-average power ratio (PAPR) performances of OFDM signals associated with a scale factor in DFnT are fully analyzed. A 38.2 Gb/s OFDM signal transmission with chaotic DFnT is successfully demonstrated over a 20 km standard single-mode fiber (SSMF), where the gain of receiver sensitivity is ∼2 dB (BER @10−3), compared with OFDM without precoding.

Dynamic reconfigurable intelligent surface deployment for physical layer security enhancement in mmWave systems

AbstractIn next‐generation wireless communications, reconfigurable intelligent surface (RIS) has emerged as a cost‐effective technique for enhancing physical layer security (PLS) in millimeter‐wave (mmWave) communications, especially under challenging scenarios with adversarial entities and obstructions. However, the primary studies for RIS incorporation in mmWave communication systems utilized static deployments, lacking adaptability and efficiency in complex environments. To address this problem, a dynamic RIS deployment design framework is introduced for PLS enhancement in mmWave systems against jamming and eavesdropping attacks. For the design, it is aimed to maximize the secrecy rate by jointly optimizing the RIS selection with the beamforming design. The resulting optimization problem is challenging to solve due to the coupling of the RIS control factor, joint beamforming design, and non‐convex constraints. To tackle these issues, an efficient multi‐RIS‐aided PLS enhancement algorithm is proposed. It transforms the objective into a series of subproblems and employs the fractional programming technique and prox‐linear block coordinate descent updating method to solve them alternatively and obtain the optimal solution. The simulations demonstrate the advantage of the dynamic deployment, which exhibits enhanced security performance with reduced complexity compared with benchmarks. Further examinations also provide insight into optimal RIS activation configurations, achieving optimal balance for securing mmWave communications against emerging threats while maintaining system efficiency.

Physical-Layer Security Enhancement in Energy-Harvesting-Based Cognitive Internet of Things: A GAN-Powered Deep Reinforcement Learning Approach

Physical-Layer Security Enhancement in Energy-Harvesting-Based Cognitive Internet of Things: A GAN-Powered Deep Reinforcement Learning Approach

Multi-band chaotic non-orthogonal matrix-based encryption for physical-layer security enhancement in OFDM-PONs

In this paper, we propose and experimentally demonstrate a novel multi-band chaotic non-orthogonal matrix (CNOM)-based encryption scheme for secure orthogonal frequency division multiplexing (OFDM) passive optical networks. The dimension of non-orthogonality is exploited in the encryption with the CNOM, where both faster-than-Nyquist signaling and redundant precoding were employed to dynamically scramble the original number of subcarriers of each sub-band and fix the overall data rate. Both simulation and experimental results of a 10.6 Gb/s 4-QAM transmission over a 20-km standard single-mode fiber showed that the total key space significantly increases by 1.4×10482 and 1.72×10653 times, as the number of sub-bands increases from 1 to 10 and 15, with a considerable reduction in computational complexity of 90% and 93.33% in complex-valued multiplication, and 90.76% and 94.12% in complex-valued addition, when encrypting one OFDM symbol, respectively. Moreover, the improved resilience to the frequency roll-off has also been verified by using additional permutation matrices in the proposed encryption algorithm.

Physical Layer Security Enhancement Using Reconfigurable Intelligent Surfaces and Multi-antenna Energy Harvesting

Physical Layer Security Enhancement Using Reconfigurable Intelligent Surfaces and Multi-antenna Energy Harvesting

High-security 3D CAP modulation scheme based on a pyramid constellation design for 7-core fiber.

This paper proposes a 3-dimensional (3D) carrier-less amplitude and phase modulation (CAP) based on a pyramid constellation design encryption scheme for 7-core fiber in passive optical network (PON). The chaos sequences generated by the 4D hyperchaotic system are applied to produce the masking factor, and the pyramid Rubik's cube rotation rules are used to flip and rotate the constellation points. To verify the performance of the proposed 3D CAP-PON system, 25.5Gb/s encrypted Pyraminx-3D-CAP-16 signal transmission over 2 km 7-core fiber is experimentally demonstrated. Compared with the traditional 3D-CAP-16 signal, the proposed Pyraminx-3D-CAP-16 signal achieves a sensitivity gain of 0.5 dB under the limit of hard decision forward error correction (HD-FEC) 3.8 × 10-3. Compared with the Pyraminx-3D-CAP-16 signal, the encrypted Pyraminx-3D-CAP-16 signal has little difference from that before encryption, which has a great application prospect in the physical layer security enhancement of the 3D-CAP-PON system.

Deep Reinforcement Learning for Physical Layer Security Enhancement in Energy Harvesting Based Cognitive Radio Networks

The paper studies the secrecy communication threatened by a single eavesdropper in Energy Harvesting (EH)-based cognitive radio networks, where both the Secure User (SU) and the jammer harvest, store, and utilize RF energy from the Primary Transmitter (PT). Our main goal is to optimize the time slots for energy harvesting and wireless communication for both the secure user as well as the jammer to maximize the long-term performance of secrecy communication. A multi-agent Deep Reinforcement Learning (DRL) method is proposed for solving the optimization of resource allocation and performance. Specifically, each sub-channel from the Secure Transmitter (ST) to the Secure Receiver (SR) link, along with the jammer to the eavesdropper link, is regarded as an agent, which is responsible for exploring optimal power allocation strategy while a time allocation network is established to obtain optimal EH time allocation strategy. Every agent dynamically interacts with the wireless communication environment. Simulation results demonstrate that the proposed DRL-based resource allocation method outperforms the existing schemes in terms of secrecy rate, convergence speed, and the average number of transition steps.

Physical Layer Security Enhancement via Intelligent Omni-Surfaces and UAV-Friendly Jamming

Intelligent reflecting surfaces (IRS) are considered one of the prominent technologies to be adopted in 6G and beyond networks. However, one of the main IRS limitations is restricting the communication to the reflective dimension, which means that users located behind the IRS surface cannot benefit from it. In this paper, we make use of intelligent omni-surfaces (IOS), as an alternative to IRS, in addition to unmanned aerial vehicles (UAV) to achieve secure communication in an Internet-of-Things (IoT) communication system. Specifically, we propose IOS-UAV assisted communication wherein an access point (AP) tries to send confidential information to a legitimate IoT device in presence of an eavesdropper. The UAV serves two fold; it acts as a friendly jammer that is trying to degrade the signal quality at the eavesdropper and as a source of energy to power up the IoT device via simultaneous wireless information and power transfer (SWIPT) to address the limited power available to it. We formulate an average secrecy rate maximization problem, which jointly optimizes the AP and UAV transmission powers, the UAV trajectory, IOS phase shifts and power splitting factor. The formulated problem is non-convex, therefore we exploit successive convex approximation (SCA) to tackle this issue. Simulation results show that the iterative SCA solution converges rapidly. Besides, the proposed scheme outperforms the traditional system without IOS by a gap of 140% in terms of the secrecy capacity.

Physical Layer Security Enhancement via IRS Based on PD-NOMA and Cooperative Jamming

Physical Layer Security Enhancement via IRS Based on PD-NOMA and Cooperative Jamming

Physical-layer security enhancement using artificial noise for D2D communication in vehicular platooning networks

In this article, we introduce physical-layer security enhancement technique based on artificial noise for secure device-to-device (D2D) communications within a platoon in vehicular platooning networks. In particular, we consider a scenario that two D2D-enabled platoons are on the same way. All the vehicles in one platoon are used to generate artificial noise to enhance the secrecy of D2D communications within the other platoon against information leakage to a potential eavesdropping vehicle. We propose artificial noise generation strategies by the platoon according to the assumption on channel state information (CSI): full-CSI and partial CSI assumptions. We further analyze the effect of artificial noise depending on the relationship between the number of vehicles in two platoons. We finally evaluate the performance of our proposed schemes in terms of secrecy rate through extensive simulations and provide useful intuitions for secure platooning.

A Novel Algorithm for Network Enhancement JUP and Rate Scheduling in mmWave for 5 G Networks

Abstract: Because of the open nature of the wireless medium, which renders wireless transmission subject to eavesdropping and hostile attacks, security and privacy have become increasingly important aspects in wireless communication networks. The introduction and development of decentralised and ad-hoc wireless networks has posed significant obstacles for implementing higher-layer key distribution and management in practise. As a result, physical layer security has emerged as a feasible method for enabling safe transmission while keeping complexity to a minimum. We might use this technique to focus on physical layer security design and enhancement in wireless networks

Secure OFDM-PON using three-dimensional selective probabilistic shaping and chaos.

In this paper, a novel three-dimensional selective probabilistic shaping (3D-SPS) and chaos-based multi-stage encryption scheme is proposed for physical layer security enhancement and transmission performance improvement in orthogonal frequency division multiplexing-based passive optical network (OFDM-PON). On the basis of inherent randomness of symbol sub-sequences with low granularity, the SPS algorithm is performed on the employed cubic constellation within each sub-sequence. Consequently, the probability distribution of inner points significantly increases after the constellation region exchange according to various rules. The generated compressed shaping information (CSI) is encrypted and used as the synchronization head for transmission. Furthermore, 3D scrambling is performed while maintaining the shaping effect. The encrypted signals of 35.3 Gb/s are successfully transmitted over a 25-km standard single-mode fiber (SSMF) and a back-to-back (BTB) system. The results show that by selecting the appropriate system parameter, the proposed scheme can provide about 2.4 dB modulation gain on the received optical power at a bit error rate (BER) of 10‒3 compared with a conventional quadrature amplitude modulation (QAM) signal under the same bit rate, and 0.9 dB shaping gain is brought due to the SPS. The encryption method possesses a relatively low computational complexity and sufficient key space of 10120 is introduced to resist exhaustive attack.

Security enhancement for adaptive optics aided longitudinal orbital angular momentum multiplexed underwater wireless communications.

The frozen-wave-based longitudinal orbital angular momentum multiplexing (LOAMM) system developed in [IEEE Photonics J.10, 7900416 (2018)10.1109/JPHOT.2017.2778238] has the potential to overcome the crosstalk effects induced by turbulence. In this paper, we propose a defocus measurement aided adaptive optics (DMA-AO) technique for turbulence compensation in a LOAMM underwater wireless optical communication (UWOC) system to investigate the enhancement of physical layer security. Relying on a phase retrieval algorithm and probe beam, three amplitude-only measurements obtained from different back focus planes can realize phase reconstruction of distorted OAM beams. Moreover, the so-called mixture generalized gamma-Johnson SB (GJSB) distribution is proposed to characterize the probability density function (PDF) of reference-channel irradiance of OAM. The GJSB allows for obtaining closed-form and analytically tractable expression for the probability of strictly positive secrecy capacity (SPSC) in a single input single output (SISO) system. Furthermore, the average secrecy capacity (ASC) and probability of SPSC for a multiple input multiple output (MIMO) system are investigated. Compared to the traditional OAM multiplexing system based on Laguerre-Gaussian (LG) beams, the LOAMM system with a probe beam assisted DMA-AO technique has potential advantages for improving the security performance in UWOC.

Cooperative communication design of physical layer security enhancement with social ties in random networks

Social relationships among wireless nodes play a key role of wireless networks to establish trusted services applications. Owing to inherent randomness of wireless environment, the security and confidentiality of wireless information transmission urgently needs to be addressed. Physical layer security (PLS) technique has been proposed as an effective solution of securing wireless communications, by exploiting channel characteristics. Different from most previous works that ignored relationship among wireless nodes, this paper studies secrecy performance of cooperative communication based random network with social friendships, and presents four types of cooperative relaying and jamming schemes. In particular, proposed schemes introduce the concept of Local Friendship Circle (LFC) and Long-range Friendship Annulus (LFA), in which the optimal relay and friendly jammers are selected based on their physical locations and channel state information (CSI). In the context of PLS, the connection outage probability (COP) and secrecy outage probability (SOP) are introduced to evaluate performance of designed strategies, and their mathematical expressions are derived with the tools of stochastic geometry. Numerical simulations validate the theoretical analysis and illustrate the influence of system configurations on reliability and security performances.

Antenna Additively Manufactured Engineered Fingerprinting for Physical-Layer Security Enhancement for Wireless Communications

Physical layer security is increasingly being exploited as a technique to enhance the security of wireless communications. Well-known hardware security techniques leverage unintended manufacturing process variations or fixed unique hardware structures in the semiconductors for identification of different copies of an RF system. The fundamentally different concept of engineering a unique fingerprint for each antenna produced, by leveraging additive manufacturing, is presented in this work. To the best of the author’s knowledge, this is the first application of the concept of radio frequency (RF) fingerprint engineering using additively manufactured (AM) antennas for hardware-based security mechanisms. AM engineered fingerprints (AMEF) are based on intentional features added to antenna’s geometries using 3D printing, enabling more accurate signal source identification and classification. Such unique features per unit produced would be prohibitively costly by using traditional photolithographic processes. The AMEF concept is validated using AM right hand circularly polarized (RHCP) truncated corner probe fed (TCPF) patch antennas and a testbed setup with software-defined radios and MATLAB implementations to create, transmit, receive, and prepare a convolutional neural network (CNN) to classify the transmitted raw I/Q data of Wi-Fi signals (IEEE 802.11). The AMEF technique greatly improves the physical layer security performance limitations in large-scale applications where the features of the devices can overlap, at a low-cost and low production time impact, and it allows the use of the antenna features for both individual and type classification and identification of RF sources.

Coalitional game based joint beamforming and power control for physical layer security enhancement in cognitive IoT networks

In this paper, the physical layer secure transmission in multi-antenna multi-user cognitive internet-of-thing (IoT) network is investigated, where the coalitional game based joint beamforming and power control scheme is proposed to improve the achievable security of cognitive IoT devices. Specifically, the secondary network consisting of a muti-antenna secondary transmitter, multiple secondary users (SUs), is allowed to access the licensed spectrum resource of primary user (PU) with underlay approach in the presence of an unauthorized eavesdropper. Based on the Merge-Split-Rule, coalitional game is formulated among distributed secondary users with cooperative receive beamforming. Then, an alternative optimization method is used to obtain the optimized beamforming and power allocation schemes by applying the up-downlink duality. The simulation results demonstrate the effectiveness of our proposed scheme in improving the SU's secrecy rate and system utility while guaranteeing PU's interference threshold.

Physical Layer Intercept Probability in Wireless Sensor Networks over Fisher–Snedecor \({\mathcal{F}}\) Fading Channels

In this paper, we analyze the physical layer security (PLS) of an arbitrarily dimensioned wireless sensor network (WSN) in the presence of an unauthorized attacker. Various scheduling schemes have been exploited in order to enhance the secure transmission of reliable links impaired by Fisher–Snedecor F fading. The path loss among active nodes is also considered. The exact intercept probability expressions are derived recalling an optimal scheduling scheme (OS), a scheduling policy based on a specific cumulative distribution function (CS), and round-robin scheduling as a baseline. The asymptotic behavior of the intercept metric is also presented in a simpler form with acceptable accuracy. The secrecy diversity orders are defined and the security–reliability tradeoff of WSN is specified. Numerical results are provided to demonstrate the interplay of various main/wiretap channel conditions, the distances among nodes, the number of active sensors, and the average main-to-eavesdropper’s signal ratio in order to upgrade the quality of the WSN secrecy performance. Additionally, the impact of the outage probability on the intercept probability is defined for a variety of scenarios under which either the CS or OS scheme could be selected as suitable for PLS enhancement. The obtained results are verified by independent Monte Carlo simulations.

A Physical Layer Security Enhancement Scheme under the Ambient Backscatter System

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.

On the Physical Layer Security of Underlay Relay-Aided Device-to-Device Communications

In this paper, we study the underlay relay-aided Device-to-Device (D2D) communications to improve the physical layer (PHY) security of the cellular network. We propose a cooperative scheme, whereby the D2D pair, in return of being allowed to share the spectrum band of the cellular network, serves as a friendly jammer, through its multiple-input multiple-output relay, to degrade the wiretapped signal at an eavesdropper. This paper aims to show that spectrum sharing is advantageous for both D2D communications and cellular networks with respect to reliability and robustness for the former, and the physical layer security enhancement for the latter. To assess the proposed cooperative system model, closed-form expressions for the D2D outage probability, the secrecy outage probability, and the probability of non-zero secrecy capacity are derived. More importantly, the benefits due to the cooperation scheme are verified through numerical and simulation results.

Secure mmWave UAV-Enabled SWIPT Networks Based on Random Frequency Diverse Arrays

In this article, we investigate physical layer security enhancement methods for millimeter-wave (mmWave) simultaneous wireless information and power transfer (SWIPT) unmanned aerial vehicle (UAV) networks, where the power-limited destination decodes the information and harvests energy from the received radio-frequency signals. Considering the effect of beamforming design and actual 3-D antenna gain, the directional modulation (DM) technique based on random frequency diverse array (RFDA) is adopted to guarantee security. The closed-form expressions of the lower bound of average secrecy rates with uniform linear array (ULA) and uniform planar array (UPA) are derived, respectively. Furthermore, based on the theoretical analysis results, we formulate the secrecy rate maximization problem subject to the energy harvesting constraint at the destination. Then, a suboptimal iterative optimization algorithm is proposed to solve the secrecy rate maximization problem by optimizing the transmit power, power splitting ratio, and UAV trajectory jointly. The simulation results show that the average secrecy rate of RFDA scheme is much larger than the conventional phase array scheme, especially when using ULA. The proposed optimization algorithm can achieve a higher average secrecy rate than other benchmark algorithms.