Cyber terrorism is a controversial term. In considering terrorism, the popular image is of hijacked aeroplanes, buildings and lives destroyed by bombs, multiple shootings and other large-scale life-threatening incidents. It would be easy to marginalise cyberterrorism as nothing more important as a bit of hacking, a few leaked emails and passwords, a website blocked. Unfortunately, one must consider the scenario in which a cyberterrorist takes control of important infrastructure, transport systems, power grids, and defence installations. Where a network of terrorists might organise a large-scale terror attack involving conventional weapons, the cyberterrorist might take control of or even destroy infrastructure on which millions of lives depend.