In February of this year, Homeland Security Secretary Jeh Johnson noted that cybersecurity is one of the most important missions of the Department of Homeland Security*. Indeed, as the country and the global community become more dependent on computers and computer networks, America’s adversaries, whether nation-states, criminals, or terrorists, will increasingly seek to exploit vulnerabilities in US computer networks in order to undermine America’s economy and national security. In this context, there are three categories of threats that will be of increasing concern: cyberespionage, cybercrime, and cybersabotage. Let us look at each of them separately.