What triggers degraded operations in data-link security?

• A. Compromise of encryption/authentication
• B. Routine maintenance with no security impact
• C. High signal-to-noise ratio
• D. Clear line-of-sight

Answer: (A)

When data-link security relies on encryption and authentication to protect messages, any breach of those protections undermines trust in the channel. If encryption or authentication is compromised, the system typically downgrades to a safe, reduced-security mode to limit risk, which is what we mean by degraded operations. This could mean disabling certain features, requiring additional verification, or pausing secure communications until the issue is addressed.

Routine maintenance with no security impact doesn’t affect security status, so it wouldn’t trigger degradation. A high signal-to-noise ratio indicates a clearer channel and better performance, not a security failure. Clear line-of-sight is about physical visibility of the link and likewise doesn’t directly impact security guarantees.