Secret key distribution leveraging color shift over visible light channel

Abstract

Given the widely adoption of screen and camera in many electronic devices, the visible light communication (VLC) over screen-to-camera channel emerges as a novel short range communication technique in recent years. Active research explores various ways to convey messages over screen-camera channel, such as barcode and unobtrusive optical pattern. However, with the prevalence of LED screens of wide viewing angles and mobile devices equipped with high standard cameras, the threat of information leakage over screen-to-camera channel becomes in-negligible. Few studies have discussed how to ensure the security of data transmission over screen-to-camera channel. In this paper, we propose a secret key distribution system leveraging the unique color shift property over visible light channel. To facilitate such design, we develop a practical secret key matching based method to map the secret key into gridded optical patterns on screen, which can only be correctly recognized by the legitimate user through an accessible region and allow regular data stream transmission through valid grids. The proposed system is prototyped with off-the-shelf devices and validated under various experimental scenarios. The results show that our system can achieve high bit-decoding accuracy for the legitimate users while maintaining comparable data throughput as regular unobtrusive VLC systems with very low recovery accuracy of the encrypted data for the attackers.

GPSKey: GPS based Secret Key Establishment for Intra-Vehicle Environment

“…As the user does not need to directly type PINs or confirm the pairing process, these schemes remove the requirement of human intervention for the device pairing process. A common idea of the contextbased key establishment methods is that legitimate devices co-located within the same space may acquire highly similar sensor observations (e.g., ambient light and audio signal [23], acoustic signals [30], color shift observation over light channel [18], wireless signal strength [13] or wireless channel state information [19], [22]). However, these approaches share the following shortcomings: (1) they can be easily affected by environmental interferences (e.g., noise), (2) the user may need to inject artificial events to decrease pairing time.…”