Spoofing Detection for Indoor Visible Light Systems with Redundant Orthogonal Encoding

As more and more visible light communication (VLC) and visible light sensing (VLS) systems are mounted on today’s light fixtures, how to guarantee the authenticity of the visible light (VL) signal in these systems becomes an urgent problem. This is because almost all of today’s light fixtures are unprotected and can be openly accessed by almost anyone, and hence are subject to tampering and substitution attacks. In this paper, by exploiting the intrinsic linear superposition characteristics of visible light, we propose VL-Watchdog, a scalable and always-on signal-level spoofing detection framework that is applicable to both VLC and VLS systems. VL-Watchdog is based on redundant orthogonal encoding of the transmitted visible light, and can be implemented as a small hardware add-on to an existing VL system. The effectiveness of the proposed framework was validated through extensive numerical evaluations against a comprehensive set of factors.