As digital threats increasingly span across domains, cross-institutional cooperation is becoming central to national security. Contemporary digital threats blend cyber intrusion, physical sabotage, economic pressure and disinformation into single, sequenced operations. This issue was discussed at the fourth Digital Defence Symposium in Singapore, which I attended on 21 and 22 July. It demands coordination across defence, intelligence, cyber authorities, regulators, police, border force, industry and international partners. At the Digital Defence Symposium, Singapore’s Permanent Secretary for Defence, Joseph Leong, warned that technology was shifting from a tool into an actor.