The United States Department of Defense (DoD) has established security criteria for its computer systems and for those systems that perform government work under contract. Each system is evaluated and awarded a security rating, depending on the extent the system protects resources and its own processing.

Although IBM® does not claim compliance with any particular criteria, the multilevel security (MLS) functions of a z/OS Version 1 Release 5 system and higher are designed to provide a high level of security. See z/OS Planning for Multilevel Security and the Common Criteria for details.