1. The concept of processing information with different classifications and categories that simultaneously permits access by users with different security clearances and denies access to users who lack authorization. 2. A system operating in this mode is one which stores and/or processes data at various classifications etc, but for which there are users not cleared for or who need to know about all the data and whose access is restricted appropriately. See also: Dedicated Security Mode, System High Security Mode, Compartmented Security Mode.