Some common beliefs about computer security and the impact they have had on the field are discussed. In addition to identifying the myths, examples of blind adherence to the myths are given.>

Network security issues can be handled with the same concepts that apply to single computer systems. The network operating modes of Dedicated, System High and Multilevel establish the requirements for a network Reference Monitor function. It, is shown that the Reference Monitor function can be implemented in a variety of ways.

A gross identification of threats and risks based on a data classification environment and the minimum clearance level of individuals using a system is related to the levels identified in the DODCSC Trusted Computer Evaluation Criteria. A proposed set of minimum TCB levels for given threat risk environments is identified.

This note is prompted by a number of observations. - After nearly twelve years of serious work on computer security, all that can be shown is two one-shot œbrassboard' systems and one commercially supported product that integrates the DoD security policy into the operating system. - The first round of research results on computer security were useful and by 1975 the principles of secure computers were well enough understood that the first demonstration models of security kernels had been completed. [SCHI 73] - In spite of hopes to the contrary, it has been amply demonstrated that the civil sector of government and virtually all of the private sector can satisfy their information protection needs with simple physical and procedural lethods, coupled with using systems with "improved integrity". - In spite of the tiresomeness of its repetition, the fact is that the need for secure systems for important national defense applications has not been diminished in the slightest by any work that has gone on over the past twelve years.