DIACAP is the result of a NSA directed shift in underlying security paradigm and succeeds its predecessor: DITSCAP.
An interim version of the DIACAP was signed July 6, 2006 and superseded DITSCAP. The final version is titled Department of Defense Instruction 8510.01 and was signed on November 28, 2007. It supersedes the Interim DIACAP Guidance.
One major change in DIACAP from DITSCAP is the embracing of the idea of information assurance controls (defined in DoDD 8500.1 and DoDI 8500.2) as the primary set of security requirements for all automated information systems (AISs). The IA Controls are determined based on the system's mission assurance category (MAC) and confidentiality level (CL).