Book contents
- Frontmatter
- Contents
- Preface
- Notation
- List of abbreviations
- Part I Preliminaries
- Part II Information-theoretic security
- 3 Secrecy capacity
- 4 Secret-key capacity
- 5 Security limits of Gaussian and wireless channels
- Part III Coding and system aspects
- Part IV Other applications of information-theoretic security
- References
- Author index
- Subject index
5 - Security limits of Gaussian and wireless channels
from Part II - Information-theoretic security
Published online by Cambridge University Press: 07 October 2011
- Frontmatter
- Contents
- Preface
- Notation
- List of abbreviations
- Part I Preliminaries
- Part II Information-theoretic security
- 3 Secrecy capacity
- 4 Secret-key capacity
- 5 Security limits of Gaussian and wireless channels
- Part III Coding and system aspects
- Part IV Other applications of information-theoretic security
- References
- Author index
- Subject index
Summary
This chapter extends the results obtained in Chapter 3 and Chapter 4 for discrete memoryless channels and sources to Gaussian channels and wireless channels, for which numerical applications provide insight beyond that of the general formula in Theorem 3.3. Gaussian channels are of particular importance, not only because the secrecy capacity admits a simple, intuitive, and easily computable expression but also because they provide a reasonable approximation of the physical layer encountered in many practical systems. The analysis of Gaussian channels also lays the foundations for the study of wireless channels.
The application of physical-layer security paradigms to wireless channels is perhaps one of the most promising research directions in physical-layer security. While wireline systems offer some security, because the transmission medium is confined, wireless systems are intrinsically susceptible to eavesdropping since all transmissions are broadcast over the air and overheard by neighboring devices. Other users can be viewed as potential eavesdroppers if they are not the intended recipients of a message. However, as seen in earlier chapters, the randomness present at the physical layer can be harnessed to provide security, and randomness is a resource that abounds in a wireless medium. For instance, we show that fading can be exploited opportunistically to guarantee secrecy even if an eavesdropper obtains on average a higher signal-to-noise ratio than a legitimate receiver.
We start this chapter with a detailed study of Gaussian channels and sources, including multiple-input multiple-output channels (Section 5.1.2).
- Type
- Chapter
- Information
- Physical-Layer SecurityFrom Information Theory to Security Engineering, pp. 177 - 212Publisher: Cambridge University PressPrint publication year: 2011