This chapter provides a political and philosophical analysis of the values at stake in ensuring cybersecurity for critical infrastructures. It presents a review of the boundaries of cybersecurity in national security, with a focus on the ethics of surveillance for protecting critical infrastructures and the use of AI. A bibliographic analysis of the literature is applied until 2016 to identify and discuss the cybersecurity value conflicts and ethical issues in national security. This is integrated with an analysis of the most recent literature on cyber-threats to national infrastructure and the role of AI. This chapter demonstrates that the increased connectedness of digital and non-digital infrastructure enhances the trade-offs between values identified in the literature of the past years, and supports this thesis with the analysis of four case studies.