The Communications security reference article from the English Wikipedia on 24-Apr-2004
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Communications security

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Communications security (COMSEC): Measures and controls taken to deny unauthorized persons information derived from telecommunications and ensure the authenticity of such telecommunications.

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

Source: from Federal Standard 1037C and from MIL-STD-188 and from the National Information Systems Security Glossary and from the Department of Defense Dictionary of Military and Associated Terms