CamoPHYlage: Hiding Signals in Plain Sight
Adversarial mimicking techniques that evade PHY-layer detectors and enable covert communication in plain sight. CamoPHYlage studies covert transmissions whose energy distribution in time and frequency resembles ordinary traffic.
Security monitoring rarely extends to the physical layer. Alter techniques hide data in a side channel of a legitimate signal through packet length extension, spectral sub-carriers, or modulation over modulation. Mimic techniques synthesize a non-protocol-compliant signal with a target’s PHY signature, found through Bayesian optimization and neural parameter estimation from spectrograms. Measured by Fréchet Inception Distance, both are far closer to normal traffic than conventional low-probability-of-intercept signals, and a battery-powered SDR prototype reached a receiver approximately 300 m away.