“Attack” as a term of art in international law: The cyber operations context

This article examines the meanings of “attack” in international law. It points out that the term is used in two distinct bodies of that law. First, the term “armed attack” appears in the jus ad bellum, which governs when a State may resort to force as an instrument of its national policy. In that context, it serves as a condition precedent to the resort to force in self-defence pursuant to Article 51 of the UN Charter and customary international law. Second, in the jus in bello attack refers to a particular type of military operation to which various prohibitions and restrictions apply. The jus in bello, or international humanitarian law, establishes rules as to how operations may be conducted during an armed conflict. The article examines and analyses these usages both to distinguish them from each other and to better inform the non-legal community as to their legal significance.