Название: Cryptography and Satellite Navigation
Автор: Joseph J. Rushanan, James T. Gillis
Издательство: Artech House
Год: 2025
Страниц: 351
Язык: английский
Формат: pdf (true), epub
Размер: 12.9 MB

Cryptography and Satellite Navigation is a comprehensive guide that offers a wide-ranging yet approachable introduction to the world of cryptography, with a particular focus on its role in navigation. In an increasingly connected world, cryptography serves as the cornerstone of secure communication, safeguarding information across countless cyber and navigation applications. The book includes a thorough explanation of the three primary cryptographic methods. Symmetric ciphers provide confidentiality through shared keys, while hashes play a crucial role in ensuring the integrity of information. Asymmetric, or public key cryptography, introduces a level of security through confidentiality and authentication, uniquely using private information to establish digital signatures. The book contains an insightful exploration of quantum computing and its profound implications for the future of cryptography.

Our goal is to show how cryptography could, is, and should be used to achieve assurance for satellite-based positioning, navigation, and timing (PNT), which we denote as satnav. This introduction gives a foundational overview of the central concepts in assured navigation and their associated history in preparation for subsequent deeper explorations of the supporting topics.

Most personal electronic devices give position and time automatically, and from that, navigation easily follows. In practice, satnav systems like a Global Navigation Satellite System (GNSS), infrastructure such as the Global Positioning System (GPS), or a Regional Navigation Satellite System (RNSS) set of satellites such as the Quasi-Zenith Satellite System (QZSS) contribute to that position, navigation, and timing data.1 As with any other kind of information service, the assumption is that this information is true—that one can believe the position and time are what we are given. That belief is our informal definition of PNT assurance: the degree to which a user can trust that PNT is accurate. This notion is formalized later.

Assurance, in general, is achieved by putting protections in place to mitigate anything that would cause the information to deviate from truth. In cybersecurity, the whole subject of system security engineering exists there to develop methods to provide assurance. Adapting that thinking to the PNT world has been considered, as discussed later in this chapter, but delving into those broad areas is beyond our scope.

Instead, we focus on one aspect of security engineering: cryptography, which is a large class of protection methods applied to digital information. Cryptographic methods have been applied to satnav even though much of the information being protected is not traditional digital information. These non-typical uses of cryptography for satnav are often challenging for users, who may not be familiar with cryptography. Our goal is to alleviate that challenge, bringing us to this book’s mission, which is:

Present the how and why of cryptographic methods and show where they are and can be applied to assure satnav.
As a corollary, the authors have spent the last decades working in the intersection of these two fields. Our biggest hope is that our experience will educate and motivate our reader.

Who Is This Book For?
Any book that tries to blend together two technical and almost nonoverlapping areas has the challenge of establishing its audience. As we mentioned, the use of cryptography in satnav is often obscure to navigation professionals, who may lack in-depth knowledge in cryptography, and thus those individuals are a prime target for this book. Our discussion of cryptography, arguably brief when compared to the numerous, excellent books devoted specifically to that topic, will hopefully suffice as a gentle reference and reminder as new methods are developed.

At the same time, we also have a separate target audience and one perhaps more challenging to please. We have observed that explaining the need for cryptographic methods in navigation to a cryptography professional is challenging, largely because the information that is being protected, namely the navigation signals broadcast from a satellite, are not the traditional focus of cryptography. For example, how would one digitally sign a radio frequency (RF) signal? Thus, this book addresses where assurance methods are needed in navigation, and how cryptography can be applied. Accomplishing that requires that we offer a description of satnav that is enough to show where the cryptographic methods are applied, but not too much to overwhelm those who are not navigation engineers by training.

In summary, our intended reader is interested in the union of these two questions:
• For the navigation engineer, what are cryptographic methods and how are they used in satnav?
• For the cryptographer, what are the needs of satnav for cryptography?

Contents: