Definition: (DOD) The protection resulting from all measures designed to deny unauthorized persons information of value which might be derived from the possession and study of telecommunications, or to mislead unauthorized persons in their interpretation of the results of such possession and study. Communications security includes: cryptosecurity, transmission security, emission security, and physical security of communications security materials and information.


a. cryptosecurity--The component of communications security that results from the provision of technically sound cryptosystems and their proper use. b. transmission security--The component of communications security that results from all measures designed to protect transmissions from interception and exploitation by means other than cryptanalysis. c. emission security--The component of communications security that results from all measures taken to deny unauthorized persons information of value that might be derived from intercept and analysis of compromising emanations from crypto-equipment and telecommunications systems. d. physical security--The component of communications security that results from all physical measures necessary to safeguard classified equipment, material, and documents from access thereto or observation thereof by unauthorized persons.

Also Known As: COMSEC