DDLCritical infrastructures in industrialized nations form a highly interdependent network that must be protected against both intrinsic defects and active attacks. This requires local as well as joint situational awareness based on current, accurate, and semantically unambiguous data as well as simulations, particularly of attack scenarios, necessitating in turn automated information sharing measures that can span transitive dependency networks. Since the infrastructure elements are frequently civilianowned, providing provable assertions on the precise nature of the data shared and the extent of dissemination is crucial. In this paper, a layered graph-theoretical modeling technique is used; at a lower layer, a standards-based ontological model is described in which resources and interactions are formed into a common exchange format. From this, a simple dependency model amenable to combinatorial optimization and simulation is described, which is then also used as the foundation for the application of the schematic protection model by Sandhu to the information sharing problem.
