Secrecy Metrics Research Articles

Physical Layer Security of 6G Vehicular Networks with UAV Systems: First Order Secrecy Metrics, Optimization, and Bounds

Physical Layer Security of 6G Vehicular Networks with UAV Systems: First Order Secrecy Metrics, Optimization, and Bounds

Review of Physical Layer Security in 5G Wireless Networks

Fifth generation (5G) wireless networks promise to revolutionize the way we communicate and connect to the internet. However, as with any new technology, 5G networks also bring new security challenges that need to be addressed. One of the key areas of concern is physical layer security, which refers to the protection of the physical layer of the network against attacks that could compromise its integrity and availability. In this systematic review, we examined the current state of research on physical layer security in 5G wireless networks. Our search identified 36 relevant studies that focused on various aspects of physical layer security, including threat models, vulnerabilities, and mitigation techniques. The findings of the review suggest that whereas some progress has been made in developing physical layer security solutions for 5G networks, such as advancements in multi-antenna systems, interference exploitation, secrecy metrics, and understanding the impact of fading channels, there is still much work to be performed. Further research is needed to develop more effective security solutions and risk assessment frameworks, as well as to evaluate the effectiveness of existing solutions under different conditions and scenarios. Collaboration between industry, academia, and government agencies will also be essential to address the physical layer security challenges in 5G wireless networks. The idea of the proposal is physical layer security in 5G wireless networks. We conduct proper research on this paper and analyze 45 papers to understand this topic in depth. Our research’s integrity is built on a commitment to our core principles, which include objectivity, honesty, transparency, fairness, accountability, and stewardship. These managing ideologies aid in confirming that knowledge is innovative through the research zone.

PERFORMANCE ANALYSIS OF A POINT-TOPOINT SYSTEM UNDER ACTIVE ATTACK

—In wireless communications, security issues have become difficult due to unchangeable and unpredictable nature of the wireless medium. There are many traditional cryptographic techniques which were used previously. The physical layer security used for ensuring secure wireless communications apart from the cryptographic techniques, which is achieved after proper understanding of the nature wireless channels. Classical information theoretic secrecy is one of the metrics followed, in which, we assume that there is no(zero) leaked information at the eavesdropper which means the information decoding probability at the eavesdropper is '0'. But, practically achieving classical information theoretic secrecy is not possible. So, this project deals with partial secrecy. The partial secrecy of a system is measured in terms of equivocation, which gives the information of the level at which the eavesdropper (active) is confused. It means that in partial secrecy, there is information leakage but the eavesdropper cannot exactly decode the original message. The new secrecy metrics used GSOP (generalized secrecy outage probability), AFE (average fractional equivocation) and AILR (average information leakage rate) altogether provides more comprehensive and in-depth understanding of the secrecy performance over the fading channels.

Physical Layer Security of Dual-Hop Hybrid FSO-mmWave Systems

Hybrid free-space optical (FSO) and millimeter wave (mmWave) systems have been proposed as an efficient solution to improve spectral efficiency and maintain link reliability. The comparable supported data rate and the complementary characteristics in different weather conditions of both links, i.e., FSO and mmWave) have attracted research efforts towards analyzing the different performance aspects of hybrid FSO-mmWave systems. Following this direction, in this article, the physical-layer security analysis of the dual-hop hybrid FSO-mmWave systems is addressed. In the considered system, both FSO and mmWave links are simultaneously used to carry data at each hop, while an eavesdropper is assumed to present to wiretap either one or both links. The analysis includes building a mathematical framework to derive different secrecy metrics, such as the average secrecy capacity, secrecy outage probability and effective secrecy throughput metrics, in mathematical expressions. Obtained analytical results are verified using Monte Carlo simulations where exact matching are achieved. Moreover, the presented results include investigation of the impact of the different operational parameters on the overall secrecy performance.

Restricting passive attacks in 6G vehicular networks: a physical layer security perspective

Modern wireless technologies confirm the massive connectivity with sufficient data rate in intelligent transportation systems. Passive attacks may compromise the user’s transmission with increased amenities. Physical layer security can protect transmissions. The paper investigates outage probability (OP) and secrecy outage probability (SOP) for 6G enabled vehicular networks with passive eavesdroppers. The work considers the vehicular to infrastructure scenario with re configurable intelligent surfaces (RIS) instead of power-hungry roadside units. The vehicles and passive eavesdroppers are equipped with dual antennas. Specifically, for 6G vehicular networks, this work presents the analytical expressions for the received signal-to-noise ratio (SNR). We derive first-order secrecy metrics, such as outage probability and secrecy outage probability, from SNR expressions. We have derived SNR expressions for two initial receiver locations (near and far from the legitimate). Due to their robustness towards road parameters and signal parameters, the developed expressions aid in designing and simulating secrecy systems. We conclude that RIS can be more effective than regular access points because no major fluctuations have been observed in secrecy metrics under the influence of RIS.

Security in Diffusive Molecular Timing Channels: An Amount of Confusion Level Perspective

Secure transmission of information to a desired receiver is an important attribute of any molecular communication system. This paper analyzes the secrecy performance for a multi-particle diffusive molecular timing channel. We first obtain the fractional equivocation and then employ three standard secrecy performance metrics, namely, generalized secrecy outage probability, average fractional equivocation, and average information leakage rate to evaluate the secrecy performance of the channel in the presence of an eavesdropping user. We then propose a new secrecy performance metric, the amount of confusion level, which quantifies the severity of the confusion level at the eavesdropping user. Compared to the aforementioned metrics which are mainly based on the first-order statistics, the amount of confusion level is a second order measure that characterizes the eavesdropping effect in a better way, especially in environments with very small value of the Lévy noise parameter. The dependence of various secrecy metrics on various physical parameters, especially the Lévy noise parameter and the degradation rate of information molecules, is studied. Our analysis suggests that an increase in the value of each of these parameters results in an improvement in the secrecy performance. Numerical results corroborate the derived analytical findings.

Secrecy Capacity of Time Reversal Beamforming for Multi-User MIMO System under Spatial Correlation

In this paper, for strengthening the security of wireless transmission system, the time reversal (TR) beamforming method is proposed for the downlink of multi-user MIMO system with multiple users who potentially act as eavesdroppers. We develop a multi-input, single-output, multi-eavesdropper (MISOME) wiretap channel model in which Rayleigh fading and spatial correlation are taken into account. Using the proposed model, we further analyze the confidentiality provided by TR beamforming and we use achievable secrecy rates as our performance metrics. In particular, we derive novel closed-formed expressions for the average secrecy-SINR and the mean secrecy sum-rate in order to characterize the influences of propagation conditions on network secrecy metrics. These expressions provide deeper insights into the impact of network interference on communication confidentiality. We find that TR beamforming can deliver the maximum secrecy capacity potential in uncorrelated Rayleigh channels and achieve perfect confidential communication without any extra secrecy cost. On the other hand, even weak inter-user correlation may cause a significant loss of achievable secrecy sum-rate and therefore result in high secrecy cost. But benefiting more from larger signal bandwidth and rich-scattering environment, the TR beamforming technique is still an attractive and cost-effective solution for low-power indoor applications.

Cooperative jamming in downlink satellite network with hardware impairments

AbstractIn this article, a land mobile satellite communication network with an external jammer to fight against the eavesdropper is investigated, where the hardware impairments are introduced to make the analyses more practical. It is worth noting that three jamming schemes, that is, the Gaussian noise jamming, the friendly jamming, and the scheme without jamming, are taken into account to explore the effect of the jammer comprehensively. The secrecy metrics such as the connectivity outage probability (COP), the security outage probability, and the secrecy throughput (ST), are derived for the passive eavesdropping scenario, while the ergodic secrecy capacity is analyzed for the active eavesdropping scenario. Moreover, to get intuitive insight from the closed‐form expressions, the asymptotic ST and the asymptotic COP under the condition of high signal‐to‐noise ratio are also considered. Finally, all the derivations are validated by Monte Carlo simulations, and the effects of different parameters on the performance of the network are analyzed.

On the Physical Layer Security of Mixed FSO-RF SWIPT System With Non-Ideal Power Amplifier

Free-space optical (FSO) links are contemplated as a potential paradigm to yield efficient point-to-point communication in wireless systems. Notably, these links are used to provide the proficient wireless connectivity between the radio frequency (RF) wireless network and the fiber optic-based network. To this end, more attention has been paid to mixed FSO-RF systems where single-hop FSO transmission and single-hop RF transmission configuration is used. In this paper, we propose a mixed FSO-RF dual-hop simultaneous wireless information and power transfer (SWIPT) relaying system in the presence of power amplifier (PA). It is assumed that FSO links suffer from Málaga (M)-turbulence with pointing errors and RF links experience the double shadowed Rician fading. Particularly, the physical layer security is analyzed by deriving the closed-form expressions for secrecy metrics such as secure outage probability, strictly positive secrecy capacity, and secrecy throughput. We consider the three scenarios: 1) FSO-side eavesdropping attack 2) RF-side eavesdropping attack 3) Simultaneous FSO- and RF-side eavesdropping attacks. The asymptotic approximations for the final results are also derived to obtain secrecy diversity order. The effect of SWIPT parameters and PA efficiency on the secrecy performance are then further investigated in detail. In summary, the results show that the reliability and security of the proposed system can be enhanced by utilizing efficient PAs at the RF front end depending on the eavesdropper's location and can also be controlled by the SWIPT parameters.

Unified Framework for Secrecy Characteristics With Mixture of Gaussian (MoG) Distribution

The mixture of Gaussian (MoG) distribution was proposed to model the wireless channels by implementing the completely unsupervised expectation-maximization (EM) learning algorithm. With the high convenience for density estimation applications, the focus of this letter is supposed to investigate the secrecy metrics, including secrecy outage probability (SOP), the lower bound of SOP, the probability of non-zero secrecy capacity (PNZ), and the average secrecy capacity (ASC) from the information-theoretic perspective. The above-mentioned metrics are derived with simple and unified closed-form expressions. The effectiveness of our obtained analytical expressions are successfully examined and compared with Monte-Carlo simulations. One can conclude that this letter provides a simple but effective closed-form secrecy analysis solution exploiting the MoG distribution.

Physical Layer Security Over Mixture Gamma Distributed Fading Channels With Discrete Inputs: A Unified and General Analytical Framework

Physical layer security is investigated over mixture Gamma (MG) distributed fading channels with discrete inputs. By the Gaussian quadrature rules, closed-form expressions are derived to characterize the average secrecy rate (ASR) and secrecy outage probability (SOP), whose accuracy is validated by numerical simulations. To show more properties of the finite-alphabet signaling, we perform an asymptotic analysis on the secrecy metrics in the large limit of the average signal-to-noise ratio (SNR) of the main channel. Leveraging the Mellin transform, we find that the ASR and SOP converge to some constants as the average SNR increases and we derive novel expressions to characterize the rates of convergence. This work establishes a unified and general analytical framework for the secrecy performance achieved by discrete inputs.

Authentication and Secrecy of Multicast Communication Scenario: Artificial Noise-Aided Costas Sequence Matrix FDA Approach

In multicast communication scenario, the desired users are decomposed into M groups to receive private M useful data from the transmitter, while eavesdroppers (Eves) group tries to intercept. Since wireless security system consists of authentication and secure transmission, we propose directional modulation (DM) artificial noise (AN) matrix-aided Costas sequence (CS) matrix frequency diverse array (FDA) in multicast precoding systems in this paper. Specifically, we utilize the CS matrix for desired groups authentication (i.e., group identity), and it is shared via a low-speed forward link in advance. Next, we design AN matrix-aided FDA to offer robust antieavesdropping method based on leakage concept. Furthermore, we devise secrecy metrics, namely, secrecy outage probability (SOP), asymptotic Eve’s detectability error probability, and average useful data leakage rate, based on the scenario where Eve’s instantaneous channel state information (CSI) is unavailable. In addition, we numerically analyze the proposed energy beamforming focusing and evaluate the secrecy energy efficiency. Via simulation results, the proposed scheme gives important insights into how to design and measure secrecy performances in multicast scenarios.

On the Secrecy Performance and Power Allocation in Relaying Networks With Untrusted Relay in the Partial Secrecy Regime

Recently, three useful secrecy metrics based on the partial secrecy regime were proposed to analyze secure transmissions on wireless systems over quasi-static fading channels, namely: generalized secrecy outage probability, average fractional equivocation, and average information leakage. These metrics were devised from the concept of fractional equivocation, which is related to the decoding error probability at the eavesdropper, so as to provide a comprehensive insight on the practical implementation of wireless systems with different levels of secrecy requirements. Considering the partial secrecy regime, in this paper we examine the secrecy performance of an amplify-and-forward relaying network with an untrusted relay node, where a destination-based jamming is employed to enable secure transmissions. In this regard, a closed-form approximation is derived for the generalized secrecy outage probability, and integral-form expressions are obtained for the average fractional equivocation and the average information leakage rate. Additionally, equal and optimal power allocation schemes are investigated and compared for the three metrics. From this analysis, we show that different power allocation approaches lead to different system design criteria. The obtained expressions are validated via Monte Carlo simulations.

Inducing Information Stability to Obtain Information Theoretic Necessary Requirements

This work presents a new methodology for obtaining information theoretic necessary conditions directly from general operational requirements. This methodology is based on the construction of a discrete random variable that, when conditioned upon, ensures information stability of quasi-images. The induced information stability allows a more direct way to develop information theoretic necessary conditions from operational requirements beyond using Fano’s inequality. That is, while Fano’s inequality uses the probability of error to establish an upper bound on the entropy of a random variable given its estimator, the proposed new methodology can be applied to arbitrary operational requirements to obtain corresponding conditions on information theoretic quantities. To demonstrate its power, this new methodology is employed, to derive new necessary conditions for keyed authentication over a discrete memoryless channels and to establish the capacity region subject to finite leakage and finite error of the wiretap channel under two different secrecy metrics. These examples establish the usefulness of the proposed methodology.

Secrecy Characteristics With Assistance of Mixture Gamma Distribution

Considering the fact that the mixture gamma (MG) distribution is a general model that can be used to elaborate most well-known distributions, including small-scale, large-scale, and composite fadings, this letter studies the security issue when the received signal-to-noise ratios (SNRs) follow MG distributions. Closed-form expressions for secrecy metrics including the secrecy outage probability (SOP), the probability of non-zero secrecy capacity (PNZ), and the average secrecy capacity (ASC), are derived. Monte-Carlo simulations are presented to corroborate the accuracy of our derived results. Our derived secrecy metrics provide a general and unified analysis framework for the quick evaluation of the secrecy issue over wireless channels, even when the main channel and wiretap channel are subject to different wireless channels.

Intrinsic Secrecy in Inhomogeneous Stochastic Networks

Network secrecy is vital for a variety of wireless applications and can be accomplished by exploiting network interference. Recently, interference engineering strategies (IESs) have been developed to harness network interference, depending on the wireless environment (node distribution, transmission policy, and channel conditions). Typically, the node spatial distribution has been modeled according to a homogeneous Poisson point process for mathematical tractability. However, such a model can be inadequate for inhomogeneous (e.g., sensor and vehicular) networks. This paper develops a framework for the design and analysis of inhomogeneous wireless networks with intrinsic secrecy. Based on the characterization of the network interference and received signal-to-interference ratio for different receiver selection strategies. Local and global secrecy metrics are introduced for characterizing the level of intrinsic secrecy in inhomogeneous wireless networks from a link and a network perspective. The benefits of IESs are quantified by simulations in various scenarios, thus corroborating the analysis. Results show that IESs can elevate the network secrecy significantly.

On the Performance of Low-Altitude UAV-Enabled Secure AF Relaying With Cooperative Jamming and SWIPT

This paper proposes a novel cooperative secure unmanned aerial vehicle (UAV) aided transmission protocol, where a source (Alice) sends confidential information to a destination (Bob) via an energy-constrained UAV-mounted amplify-and-forward (AF) relay in the presence of a ground eavesdropper (Eve). We adopt destination-assisted cooperative jamming (CJ) as well as simultaneous wireless information and power transfer (SWIPT) at the UAV-mounted relay to enhance physical-layer security (PLS) and transmission reliability. Assuming a low altitude UAV, we derive connection probability (CP), secrecy outage probability (SOP), instantaneous secrecy rate, and average secrecy rate (ASR) of the proposed protocol over Air-Ground (AG) channels, which are modeled as Rician fading with elevation-angel dependent parameters. By simulations, we verify our theoretical results and demonstrate significant performance improvement of our protocol, when compared to conventional transmission protocol with ground relaying and UAV-based transmission protocol without destination-assisted jamming. Finally, we evaluate the impacts of different system parameters and different UAV's locations on the proposed protocol in terms of ASR.

Analysis of short blocklength codes for secrecy

In this paper, we provide secrecy metrics applicable to physical-layer coding techniques with finite blocklengths over Gaussian and fading wiretap channel models and analyze their secrecy performance over several cases of concatenated code designs. Our metrics go beyond some of the known practical secrecy measures, such as bit error rate and security gap, so as to make lower bound probabilistic guarantees on error rates over short blocklengths both preceding and following a secrecy decoder. Our techniques are especially useful in cases where application of traditional information-theoretic security measures is either impractical or simply not yet understood. The metrics can aid both practical system analysis, including cryptanalysis, and practical system design when concatenated codes are used for physical-layer security. Furthermore, these new measures fill a void in the current landscape of practical security measures for physical-layer security coding and may assist in the wide-scale adoption of physical-layer techniques for security in real-world systems. We also show how the new metrics provide techniques for reducing realistic channel models to simpler discrete memoryless wiretap channel equivalents over which existing secrecy code designs may achieve information-theoretic security.

Caching-Aided Physical Layer Security in Wireless Cache-Enabled Heterogeneous Networks

Caching popular contents is a promising way to offload the mobile data traffic in wireless networks, but so far the potential advantage of caching in improving physical layer security (PLS) is rarely considered. In this paper, we contribute to the design and theoretical understanding of exploiting the caching ability to improve the transmission security in a wireless heterogeneous network. Two transmission schemes, namely Symbol-level scheme and Bit-level scheme, are considered in such network to improve PLS by utilizing the content property of cached files. In Symbol-level scheme, the base station (BS) ensures the secrecy of communication by transmitting the requested file along with a pre-cached file of the user such that the eavesdropper’s channel is degraded. In Bit-level scheme, the BS encodes the requested file with a pre-cached file to fully resist the overhearing of eavesdroppers in bit level, e.g., network coding. Accordingly, the node locations of BSs, users and eavesdroppers are first modeled as mutually independent Poisson point processes and the corresponding file access protocol is developed. We consider two scenarios where each scheme is employed respectively, and then derive analytical expressions of two secrecy metrics in terms of average secrecy rate and secrecy coverage probability. Numerical results are provided to show the significant security advantages of the proposed schemes and to characterize the impacts of the cache ability and network resources on the security performance.

On Physical Layer Security Over the Fisher-Snedecor ${\mathcal{F}}$ Wiretap Fading Channels

In this paper, we initially investigate the physical layer security over device-to-device communications, where the channel is modeled from the Fisher–Snedecor $\mathcal {F}$ distribution. To be specific, secrecy metrics, including the secrecy outage probability, the probability of non-zero secrecy capacity, and the average secrecy capacity, are well derived with exact closed-form expressions, which are given in terms of the Meijer’s $G$ -function. The accuracies of our mathematical expressions are further validated by Monte Carlo simulation results.