Which of the following is NOT a counter-countermeasure against DRFM-based deception?

• A. Encryption of communications links
• B. Multi-frequency sensing
• C. Signal integrity checks
• D. Randomized challenge-response

Answer: (A)

DRFM-based deception relies on capturing a real RF waveform and replaying or subtly altering it to convince a receiver that the signal is legitimate. Counter-countermeasures aim to verify authenticity at the physical and link levels, not just protect payload data. Encryption of communications links protects content from interception or tampering but does not address the authenticity or timing of the RF waveform itself, so it doesn’t stop a DRFM replay or spoof from fooling a receiver. In contrast, multi-frequency sensing makes deception harder by probing across bands, increasing the chance that a spoofed signal won’t survive checks across all frequencies. Signal integrity checks examine the waveform’s physical properties—timing, phase, amplitude, and modulation consistency—and can reveal replay or tampering through anomalies. Randomized challenge-response introduces an unpredictable element that a recordedDRFM replay cannot anticipate correctly in real time, identifying spoofing when a correct, dynamic response is required.