"The need to provide standard commercial-grade productivity applications as the general purpose user interface to high-assurance data processing environments is compelling, and has resulted in proposals for several different types of trusted systems. We characterize some of these systems as a class of architecture. We discuss the general integrity property that systems can only be trusted to manage modifiable data whose integrity is at or below that of their interface components. One effect of this property is that in terms of integrity these hybrid-security systems are only applicable to processing environments where the integrity of data is consistent with that of low-assurance software. Several examples are provided of hybrid-security systems subject to these limitations."
Defense Technical Information Center (DTIC): http://www.dtic.mil/dtic/