controlled security mode

A mode of system operation wherein (a) two or more security levels of information are allowed to be handled concurrently within the same system when some users having access to the system have neither a security clearance nor need-to-know for some of the data handled by the system, but (b) separation of the users and the classified material on the basis, respectively, of clearance and classification level are not dependent only on operating system control (like they are in multilevel security mode). (See: /system operation/ under "mode", protection level.)

Deprecated Term: IDOCs SHOULD NOT use this term. It was defined in a U.S. Government policy regarding system accreditation and was subsumed by "partitioned security mode" in a later policy. Both terms were dropped in still later policies.

Tutorial: Controlled mode was intended to encourage ingenuity in meeting data confidentiality requirements in ways less restrictive than "dedicated security mode" and "system-high security mode", but at a level of risk lower than that generally associated with true "multilevel security mode". This was intended to be accomplished by implementation of explicit augmenting measures to reduce or remove a substantial measure of system software vulnerability together with specific limitation of the security clearance levels of users having concurrent access to the system.