  The high mobility of Army tactical networks, combined with their close
proximity to hostile actors, elevates the risks associated with short-range
network attacks. The connectivity model for such short range connections under
active operations is extremely fluid, and highly dependent upon the physical
space within which the element is operating, as well as the patterns of
movement within that space. To handle these dependencies, we introduce the
notion of "key cyber-physical terrain": locations within an area of operations
that allow for effective control over the spread of proximity-dependent malware
in a mobile tactical network, even as the elements of that network are in
constant motion with an unpredictable pattern of node-to-node connectivity. We
provide an analysis of movement models and approximation strategies for finding
such critical nodes, and demonstrate via simulation that we can identify such
key cyber-physical terrain quickly and effectively.
