Providing trusted data and sharing secure information have become critical for warfighters in preventing mission compromise, for homeland security personnel in thwarting terrorist attacks, and for first responders in improving readiness for emergencies—all while reducing device space, weight, power, and operating costs. The answer is multilevel secure systems—systems that can run applications at different security or safety levels, from different agencies, or in multination coalitions—on a single processor, with very high assurance that each application is separate and communicates with all others only according to precisely defined security policies.