ABSTRACT
The aim of this chapter is to provide some technical background for the book. From the vast domain of computer and network technology, we pick out the elements that have had, or may have, cybersecurity implications. The dominant area is the nature of computer networks, their structure, and how they may be compromised. An important component of network security is encryption, where we outline the basic ideas and explain the potential threats from quantum computing, and the desire of governments to have backdoor encryption keys.
