Graph Homomorphisms and the Design of Secure Computer Systems

In designing and analyzing the structure and security of a large scale computer program or system, one is often interested in how it is constructed out of pieces or in the flow of information through it. The concepts of dependency, connectivity, and reparability which arise in security verification are handled well by graph theory. As is shown in this paper, graph homomorphism are particularly useful for describing the hierarchical/modular design of a system and for demonstrating the security of information flow.