Cyber‐Physical Systems and National Security Concerns

A set of international legal rules, known as
jus ad bellum
(Latin for “right to war”), provide a framework for determining whether an attack against a nation‐state was unlawful and whether it is permissible for the target state to respond with self‐defense. Over the past decade, legal scholars and government officials have struggled to determine how to apply
jus ad bellum
to attacks on computer systems. This chapter extends that analysis to attacks on cyber‐physical systems and concludes that although cyber‐physical systems present new national security challenges, the
jus ad bellum
analysis applies just as easily to cyber‐physical attacks as it does to attacks on computer systems and purely physical targets.