It has been suggested that this article or section be merged with COMSEC. (Discuss)
Communications security (COMSEC): Measures and controls taken to deny unauthorized persons information derived from telecommunications and ensure the authenticity of such telecommunications. Communicationssecurity includes cryptosecurity, transmission security, emission security, traffic-flow security. and physical security of COMSEC equipment.
cryptosecurity: The component of communications security that results from the provision of technically sound cryptosystems and their proper use. This includes ensuring message confidentiality and authenticity.
emission security (EMSEC): 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, automated information systems (computers), 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.
traffic-flow security: Measures that conceal the presence and properties of valid messages on a network. It includes the protection resulting from features, inherent in some cryptoequipment, that conceal the presence of valid messages on a communications circuit, normally achieved by causing the circuit to appear busy at all times.