MMHS is a profile and set of extensions to X.400

X.400

X.400 is a suite of ITU-T Recommendations that define standards for Data Communication Networks for Message Handling Systems — more commonly known as "email"....

 for messaging in military environments. It is NATO standard STANAG 4406 and CCEB standard ACP 123. It adds to standard X.400 email support for military requirements such as mandatory access control

Mandatory access control

In computer security, mandatory access control refers to a type of access control by which the operating system constrains the ability of a subject or initiator to access or generally perform some sort of operation on an object or target...

 (i.e. Classified/Secret/Top Secret messages and users, etc.). In particular it defines a new message format, P772 that is used in place of X.400's interpersonal message formats P2 (1984 standard) and P22 (1988 standard).

MMHS specifications are implemented by several X.400 vendors, particularly those located in Europe, such as Compucat Research, Boldon James, Deep-Secure

Deep-secure

Deep-Secure provides a range of EAL4-assured data sharing solutions for customers including UK MoD, UK Government, NATO, Australian Defence, BAE Systems...

, Thales Group

Thales Group

The Thales Group is a French electronics company delivering information systems and services for the aerospace, defense, transportation and security markets...

, Nexor and Isode

Isode Limited

Isode Limited is a software company based in the United Kingdom. Isode develops and markets messaging and directory server software based on the LDAP and X.500 protocols and SMTP, IMAP, POP3, XMPP and X.400 protocols .-History:...

.

See also

• Defense Message System
  Defense Message System
  The Defense Message System or Defense Messaging System is a deployment of secure electronic mail and directory services in the United States Department of Defense...
  
  
• Automated Message Handling System
  Automated Message Handling System
  The Automated Message Handling System is an automated message handling system that can be used to process, store, and disseminate legacy AUTODIN messages as well as Defense Message System messages...