Which document describes and accredits networks and systems in the United States Department of Defense?

The correct choice is the System Security Authorization Agreement (SSAA), which is essential for governing the security of networks and systems within the United States Department of Defense (DoD). The SSAA serves as a formal agreement that outlines the security requirements for a specific system, detailing the necessary security controls and ensuring that the system complies with applicable policies and standards.

This document is critical in the certification and accreditation process, as it provides a comprehensive review and sets the groundwork for the assurance that systems and networks are secure and can operate within the defined risk management framework. It effectively ties together the technical controls and security practices, allowing for a clearer understanding of the security posture necessary for mission success.

In contrast, other documents like FIPS (Federal Information Processing Standards), which govern standards for federal computing, or TCSEC (Trusted Computer Security Evaluation Criteria), which focuses on the evaluation of system security in a broader sense, do not specifically describe the accreditation process for individual DoD networks and systems. FITSAF, which pertains to the Federal Information Technology Security Assessment Framework, also does not specifically focus on the accreditation of DoD networks and systems. Therefore, the SSAA distinctly fulfills the requirement for describing and accrediting these systems within the DoD.