multilevel mode

[An] Information systems (IS) mode of operation wherein all the following statements are satisfied concerning the users who have direct or indirect access to the system, its peripherals, remote terminals, or remote hosts: (a) some users do not have a valid security clearance for all the information processed in the IS: (b) all users have the proper security clearance and appropriate formal access approval for that information to which they have access; and (c) all users have a valid need-to-know only for information to which they have access. [INFOSEC-99]