Real-time trust with `System Build´: lessons learned

This paper describes our experiences in designing an embedded avionics system which must satisfy both real-time processing and security requirements. Our approach centers around the use of a trusted `System Build´ concept (T. Vickers Benzel et al., 1990). When the concept was first developed, the full extent to which it would drive the design of an embedded operating system was not fully appreciated. At this point, several years later, we have had experience in designing a trusted operating system within the context of a trusted System Build approach. This paper describes the lessons learned from this approach both in terms of the benefits to security which have been achieved and the challenges in designing and building the tools to support the System Build concept