mber: MISC-2016-011 Preparing Activity: AS Applicable Forms: N/A Use/Relationship: This Data Item Description (DID) outlines the format and content of the PSSC. The PSSC is a document that cites security concepts and requirements relative to a particular system. It is prepared by the contractor to provide the Government with preliminary descriptions of security requirements and resources. This Data Item Description contains the format and content preparation instructions for data