This special issue is dedicated to the emerging topic of cybersecurity. While information security issues have been the subject of discussion for over 40 years in the community, there is an emerging awareness of the societal impact and relevance of the protection of information and systems. The value of digital information is growing dramatically. Physical systems coupled with computing devices (so-called cyber-physical systems) carry out functions that are fundamental for our society. Protecting these emerging critical digital infrastructures is an increasingly relevant objective from a military and political point of view. For this reason, cybersecurity is getting a very high level of attention not just from researchers, but also from decision makers, policy makers and the general public.