The multipolicy machine is a paradigm shift in Multilevel Secure (MLS) computer architecture. It permits an MLS system to enforce multiple, perhaps contradictory security policies. In the multipolicy machine concept, each MLS computer node is capable of enforcing a variety of security policies, and data carries policy domain codes to indicate which security policies apply. Thus, data can be transferred from one node to another and still be protected by the appropriate security policies. Metapolicies coordinate the interactions of security policies.