Defense Message System [National Security] Law and Legal Definition

The Defense Message System or Defense Messaging System (DMS) is a secure X.400-based e-mail system developed to ensure safety for critical operations, by the U.S. government in conjunction with industry partners. DMS was originally developed for the United States Department of Defense (DoD). DMS has substituted AUTODIN (automated digital network), the previous official DoD e-mail system as well as 45 separate e-mail systems that operated within the DoD.

Currently, DMS ensures secure electronic mail and directory services in the DOD. Further, DMS provides multimedia messaging, directory, and security services. In addition, DMS uses the underlying Defense Information Infrastructure (DII) network and security services in conjunction with National Security Agency (NSA) security products.

The main objective behind the creation of DMS was:

to incorporate components from a variety of leading hardware and software vendors; and

to leverage the best current and emerging messaging technologies within the Defense Information Infrastructure (DII).