Resource Allocation for Secure Gaussian Parallel Relay Channels with Finite-Length Coding and Discrete Constellations

We investigate the transmission of a secret message from Alice to Bob in the presence of an eavesdropper (Eve) and many of decode-and-forward relay nodes. Each link comprises a set of parallel channels, modeling for example an orthogonal frequency division multiplexing transmission. We consider the impact of discrete constellations and finite-length coding, defining an achievable secrecy rate under a constraint on the equivocation rate at Eve. Then we propose a power and channel allocation algorithm that maximizes the achievable secrecy rate by resorting to two coupled Gale-Shapley algorithms for stable matching problem. We consider the scenarios of both full and partial channel state information at Alice. In the latter case, we only guarantee an outage secrecy rate, i.e., the rate of a message that remains secret with a given probability. Numerical results are provided for Rayleigh fading channels in terms of average outage secrecy rate, showing that practical schemes achieve a performance quite close to that of ideal ones

Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey

This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical-layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical-layer message authentication is also introduced briefly. The survey concludes with observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials, 201

Novel Physical Layer Authentication Techniques for Secure Wireless Communications

Due to the open nature of radio propagation, information security in wireless communications has been facing more challenges compared to its counterpart in wired networks. Authentication, defined as an important aspect of information security, is the process of verifying the identity of transmitters to prevent against spoofing attacks. Traditionally, secure wireless communications is achieved by relying solely upon higher layer cryptographic mechanisms. However, cryptographic approaches based on complex mathematical calculations are inefficient and vulnerable to various types of attacks. Recently, researchers have shown that the unique properties of wireless channels can be exploited for authentication enhancement by providing additional security protection against spoofing attacks. Motivated by the vulnerability of existing higher-layer security techniques and the security advantages provided by exploring the physical link properties, five novel physical layer authentication techniques to enhance the security performance of wireless systems are proposed. The first technique exploits the inherent properties of CIR to achieve robust channel-based authentication. The second and third techniques utilize a long-range channel predictor and additional multipath delay characteristics, respectively, to enhance the CIR-based authentication. The fourth technique exploits the advantages of AF cooperative relaying to improve traditional channel-based authentication. The last technique employs an embedded confidential signaling link to secure the legitimate transmissions in OFDM systems