Steganography in VLC Systems

One of the areas in which wireless networks based on visible light communication (VLC) is considered superior to traditional radio-based communication is security. The common slogan summarizing VLC security features is WYSIWYS - "What You See Is What You Send". However, especially in the case of infrastructure downlink communication, security must be accounted for also in case of VLC. In this paper, we analyze the possibilities of implementing a steganographic channel in VLC systems on the physical (PHY) and medium access control (MAC) layers. We introduce new steganographic techniques for VLC: hiding data in dimming patterns and color visibility dimming (CVD) frames, and adapt methods previously proposed for radio networks, such as using unused header bits and pseudo-corrupted frames to hide data. We use the IEEE 802.15.7 standard as a reference model for protocol structure, but the steganographic techniques that we describe can also be used in networks based on different standards