**1. Introduction**

The Internet has become an essential part of daily life for almost everyone in society having grown far beyond its roots in the 1970s as the ARPANET, a network that was principally the domain of scientists and engineers. The popularity of the HTTP, developed at CERN in the late 1980s, led to the widespread use of the term 'the web' as a generic name for the Internet for many years, at least in the public domain. Of course, the Internet is much more than just web browsing and, in recent years, the term cyberspace has become the most popular term to describe interactions over the Internet. Yet, an unambiguous definition of the term is difficult to formulate [1].

Financial institutions underpinning the economy and the operation of national critical infrastructures, such as monitoring and control of the electricity supply, are now dependent on the Internet. A consequence of this is that cyberattacks become more costly for the victims and perversely more attractive to the criminals who carry them out [2]. The advent of the Internet of Things (IoT) and edge computing

as a new paradigm creates the potential for enhanced productivity but at the same time opens up new opportunities for cyberattacks while still being exposed to existing attack vectors such as the well-known denial of service attack (DDoS), which can take place in many forms [3].

In this chapter, we described the challenges in building an edge system that is secure against cyberattack. We begin by briefly reviewing the architecture of communications over the Internet and later consider the new challenges that follow from operating the hardware with values of voltage, frequency and current that enable more energy efficiency.
