We tend to think of health security in terms of things we can see under a microscope or feel in a fever. Pandemics, antimicrobial resistance, contaminated water, the next novel virus. These are the threats that governments plan for, that the World Health Organization tracks and that most of us instinctively recognise as matters of life and death. There is a newer threat on that list, and it does not come from a pathogen. It comes from a laptop, often thousands of miles away,