Wireless Physical Layer Security
EURASIP Journal on Wireless Communications and Networking
The issues of privacy and security in wireless communication networks have taken on an increasingly important role as these networks continue to flourish worldwide. Traditionally, security is viewed as an independent feature addressed above the physical layer, and all widely used cryptographic protocols are designed and implemented assuming the physical layer has already been established and provides an error-free link. However, with the emergence of adhoc and decentralized networks,
... r techniques, such as encryption, are complex and difficult to implement. Therefore, there has been a considerable recent attention on studying the fundamental ability of the physical layer to provide secure wireless communications. This paradigm is called Wireless Physical Layer Security. Physical layer security is an emerging research area that explores the possibility of achieving perfect-secrecy data transmission among intended network nodes, while possibly malicious nodes that eavesdrop upon the transmission obtain zero information. The breakthrough concept behind wireless physical layer security is to exploit the characteristics of the wireless channel, such as fading or noise, to provide secrecy for wireless transmissions. While these characteristics have traditionally been seen as impairments, physical layer security takes advantage of these characteristics for improving the security and reliability of wireless communication systems and networks. Information theoretic security provides the theoretical basis behind wireless physical layer security. Historically, information theoretic security, which builds on Shannon's notion of perfect secrecy, was laid in the 1970s by Wyner and later by Csiszár and Körner, who proved seminal results showing that there exist channel codes guaranteeing both robustness to transmission errors and a prescribed degree of data confidentiality. In the 1970s and 1980s, the impact of these works was limited, partly because practical wiretap codes were not available, but mostly due to the fact that a strictly positive secrecy capacity in the classical wiretap channel setup requires the legitimate sender and receiver to have some advantage (in general, a better SNR) over the attacker. In recent times, information theoretic security has witnessed a renaissance due in part to the work of Maurer in the 1990s, who proved that even when a legitimate user has a worse channel than an eavesdropper, it is possible for him to generate a secret key through public communication over an insecure yet authenticated channel. In the past few years, significant effort has been applied to the study of information theoretic security for wireless channel models, enhancing the classical wiretap channel and including more realistic assumptions which allow for opportunistic exploitation of the space/time/user dimensions of wireless channels for secret communications. The goal of this special issue is to present recent results in wireless physical layer security that capture the research trends in the field. The papers to be found in this issue provide the reader with a good overview of these trends.