Due to their broadcast nature, wireless systems are vulnerable in the physical layer. While many physical layer security techniques are being developed, current security solutions are based on encryption techniques. This paper analyzes the relation between encryption techniques and physical layer security approaches and proposes a new encryption-aware multilayer security framework. The proposed framework optimizes transmit power by taking the adopted encryption technique into account, while guaranteeing both a quality of service (QoS) level for the legitimate receiver and a secrecy constraint against the eavesdropper. Numerical results are given for two most widely used symmetric encryption techniques, the data encryption (DES) and the advanced encryption (AES) standards. Numerical results show that the proposed encryption-aware physical layer security system achieves a better power efficiency when compared to the classical physical layer security approaches.
Due to their broadcast nature, wireless systems are vulnerable in the physical layer. While many physical layer security techniques are being developed, current security solutions are based on encryption techniques. This paper analyzes the relation between encryption techniques and physical layer security approaches and proposes a new encryption-aware multilayer security framework. The proposed framework optimizes transmit power by taking the adopted encryption technique into account, while guaranteeing both a quality of service (QoS) level for the legitimate receiver and a secrecy constraint against the eavesdropper. Numerical results are given for two most widely used symmetric encryption techniques, the data encryption (DES) and the advanced encryption (AES) standards. Numerical results show that the proposed encryption-aware physical layer security system achieves a better power efficiency when compared to the classical physical layer security approaches.
Maintaining security in wireless systems has been a challenge due to the broadcast nature of wireless communication channels. Many methods have been proposed as countermeasures to eavesdropping attacks, which stand as one of the most important secrecy attack types that use the vulnerabilities of wireless channels. The majority of these methods come with the cost of additional power consumption for maintaining secrecy. In order to provide a framework that can enable a tradeoff between energy efficiency and secrecy, we provide a flexible adaptive physical layer security approach that enables tunable security levels for distinct bit streams of a single user. Our main motivation stems from the fact that not all data bits within a single bit steam require the same amount of security. The proposed adaptive power optimization framework allows the assignment of different secrecy rate constraints for distinct data streams. Via simulations, we show that the proposed approach can increase the power efficiency compared to the non-adaptive physical layer security solution, while satisfying the required secrecy constraints.
As a complement to high-layer encryption techniques, physical layer security has been widely recognized as a promising way to enhance wireless security by exploiting the characteristics of wireless channels, including fading, noise, and interference. In order to enhance the received signal power at legitimate receivers and impair the received signal quality at eavesdroppers simultaneously, multiple-antenna techniques have been proposed for physical layer security to improve secrecy performance via exploiting spatial degrees of freedom. This paper provides a comprehensive survey on various multiple-antenna techniques in physical layer security, with an emphasis on transmit beamforming designs for multiple-antenna nodes. Specifically, we provide a detailed investigation on multiple-antenna techniques for guaranteeing secure communications in point-to-point systems, dual-hop relaying systems, multiuser systems, and heterogeneous networks. Finally, future research directions and challenges are identified.
Electromagnetic induction, the earliest form of wireless energy transfer, was demonstrated by Michael Faraday in 1831, happening to be the infancy of radio communication. Since then, this technique in various scales was used for communications, eventually converging to a democratic name "Radio" in the early 1900s as we know it today. Radio frequency or RF communications are collectively and broadly referred to the communication of wireless nature using electromagnetic waves with a frequency of roughly a few kHz to several THz. RF communications are used for several applications ranging from leisure, meteorology, public broadcast, commercial, domestic and defense communications, and so forth. However, when information is communicated, often there is a need to distinguish among the intended receivers and eavesdroppers, for reasons of secrecy, confidentiality, and integrity, like for requirements from personal privacy, till national security. At present, wireless communications are mostly secured in the top level through mathematic encryption - the Advanced Encryption Standard (AES) and the Rivest-Shamir-Adleman (RSA) methods are some examples of this, and in smaller levels by techniques like range limiting, frequency diversity and similar. Anyhow the prominent mode of security is mathematic-based software encryption.Now it is apparent that researchers (ethical or unethical) are working hard like the research community in software encryption to find techniques to crack into the information transmitted. Very often a scenario is encountered such that a transmitted spectrum is recorded and is then cracked over time using several reverse engineering and computational approaches. After all, software encryption is nothing but a complicated mathematical function that, in principle, is always solvable, provided enough time and computational effort is applied to the challenge. This is like eavesdropping an unknown language speaker, recording the conversation, and then transliterating it later with the help of a proficient translator.The current advances in computing and artificial intelligence, like the advent of quantum computing makes this plot worse as computation power and competence is evolving day by day [1-4].An added fortress to wireless communication in the shadow of such an impending vulnerability is hardware security, which is interchangeably called physical layer network security. This is synonymous to adding an extra padlock alongside a combination lock that extends the security over time and effort. Thus, physical layer wireless security is a set of hardware control approaches which makes sure that an effective reception of transmitted data constellation (often software encrypted) could be received in the right format only along pre-defined secure directions or locations. The transmission along all other directions or locations is either scrambled or prevented. This is a relevant concern and is backed by the fact that in a conventional antenna-based transmission, even though the directional gain of the antenna can be controlled, the constellation pattern of transmitted data is distributed in free space almost omnidirectionally around it. Thus, a receiver of adequate sensitivity would be able to record the transmitted data even though it is encrypted mathematically.In this chapter, we broadly classify this concept, discuss several types of reported technologies for physical layer wireless security, and outline their comparisons. Finally, a future perspective of the same is drawn for readers who are interested in this promising research topic.
Wireless communications offer data transmission services anywhere and anytime, but with the inevitable cost of introducing major security vulnerabilities. Indeed, an eavesdropper can overhear a message conveyed over the open insecure wireless media putting at risk the confidentiality of the wireless users. Currently, the way to partially prevent eavesdropping attacks is by ciphering the information between the authorised parties through complex cryptographic algorithms. Cryptography operates in the upper layers of the communication model, bit it does not address the security problem where the attack is suffered: at the transmission level. In this context, physical layer security has emerged as a promising framework to prevent eavesdropping attacks at the transmission level. Physical layer security is based on information-theoretic concepts and exploits the randomness and the uniqueness of the wireless channel. In this context, this thesis presents signal processing techniques to secure wireless networks at the physical layer by optimising the use of multiple-antennas. A masked transmission strategy is used to steer the confidential information towards the intended receiver, and, at the same time, broadcast an interfering signal to confuse unknown eavesdroppers. This thesis considers practical issues in multiple-antenna networks such as limited transmission resources and the lack of accurate information between the authorised transmission parties. The worst-case for the security, that occurs when a powerful eavesdropper takes advantage of any opportunity to put at risk the transmission confidentiality, is addressed. The techniques introduced improve the security by offering efficient and innovative transmission solutions to lock the communication at the physical layer. Notably, these transmission mechanisms strike a balance between confidentiality and quality to satisfy the practical requirements of modern wireless networks.
In traditional physical layer security paradigm, no leakage of confidential information to the eavesdropper is tolerated regardless of whether the message is encrypted or not. This will result in an achievable secure transmission rate that is significantly smaller than the channel capacity. This article presents a novel approach that allows treatment of physical layer security in conjunction with encryption to achieve a flexible trade-off of system resources. We propose a novel framework to model the interplay between secured transmission rate and error probability in error prone ciphertexts. To this end, we use the concept of rate-equivocation region to establish such a connection. To clearly describe the application of our framework, we consider the case of 4-node Gaussian wiretap channel. For such a channel, we characterize the rate-equivocation region in different scenarios, and then use it to study the achievable rate of encryption-aware physical layer security. The obtained results show that, for a fixed transmission power, the prior knowledge of encryption can significantly increase the secured transmission rate. In addition, encryption-aware physical layer security can achieve a target transmission rate at a reduced transmission power compared to the conventional encryption-agnostic physical layer security.
Securing wireless communication, being inherently vulnerable to eavesdropping and jamming attacks, becomes more challenging in resource‐constrained networks such as internet‐of‐things. Towards this, physical layer security (PLS) has gained significant attention due to its low complexity. The authors address the issue of random inter‐node distances in secrecy analysis and develop a comprehensive quality‐of‐service (QoS) aware PLS framework for the analysis of both eavesdropping and jamming capabilities of the attacker. The proposed solution covers the spatially stochastic deployment of nodes. The secrecy performance is characterised against both attacks using inter‐node distance‐based probabilistic distribution functions. The model takes into account the practical limits arising out of underlying QoS requirements, which include the maximum distance between legitimate users driven by transmit power and receiver sensitivity. A novel concept of eavesdropping zone is introduced, and the relative impact of jamming power is investigated. Closed‐form expressions for asymptotic secrecy outage probability are derived offering insights into the design of optimal system parameters for desired security level against the attacker's capability of both attacks. The analytical framework, validated by numerical results, establishes that the proposed solution offers a potentially accurate characterisation of the PLS performance and key design perspective from point‐of‐view of both legitimate user and attacker.