What is the difference between communications security (COMSEC) and operational security (OPSEC) in combat networks?

• A. COMSEC protects confidentiality and integrity of communications; OPSEC protects information about operations, capabilities, and timing from adversaries.
• B. COMSEC and OPSEC are the same.
• C. COMSEC protects physical security; OPSEC protects encryption.
• D. COMSEC protects only supply chain.

Answer: (A)

The key idea here is that protecting how we communicate and protecting what we reveal about our operations are two different tasks. COMSEC focuses on the content of our communications—making sure messages stay confidential and arrive unaltered, and that cryptographic keys and authentication protect who is speaking and what is being said. In practice this includes encryption, secure channels, and key management to prevent eavesdropping or tampering.

OPSEC, on the other hand, aims to prevent adversaries from learning anything about our operations, capabilities, or timing from any information they can observe, not just the messages themselves. That means guarding how often we communicate, when we do, where we might be located, what equipment we’re using, and even seemingly routine patterns that could reveal our intent or strength.

So the best statement is the one that correctly separates these roles: COMSEC protects the confidentiality and integrity of communications, while OPSEC protects information about operations, capabilities, and timing from adversaries. The other options blur or misdefine these roles—COMSEC is not about physical security or merely encryption in isolation, and OPSEC is broader than any single aspect like encryption alone.