Note: Communications security includes cryptosecurity, transmission security, emission security, and physical security of COMSEC material.

• cryptosecurity: The component of communications security that results from the provision of technically sound cryptosystems and their proper use.
• emission security: Protection resulting from all measures taken to deny unauthorized persons information of value which might be derived from intercept and analysis of compromising emanations from crypto-equipment, AIS, and telecommunications systems.
• 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.
• transmission security: The component of communications security that results from the application of measures designed to protect transmissions from interception and exploitation by means other than cryptanalysis.