LuminaLink: Enabling Low Cost Secure Visible Light Communication with Birefringence

Visible Light Communication (VLC) offers a promising solution for wireless communication due to its large spectrum, interference resistance, and inherent security features. However, the broadcast nature of VLC signals poses significant security and privacy challenges, particularly in the context of the Internet of Things (IoT) where low-cost and resource-constrained devices are prevalent. In this paper, we introduce LuminaLink, a novel position-based VLC system designed to establish a secure communication link between a transmitter and a receiver located at a designated position. Leveraging the principle of birefringence, LuminaLink encodes messages using Color-Shift Keying (CSK), ensuring that only the receiver at the specified position can correctly decode the transmitted information. To achieve this, we design an innovative interference chip using transparent adhesive tape as a birefringence material, making LuminaLink both cost-effective and easy to deploy. Our system eliminates the need for expensive cryptographic algorithms by employing an initialization process that establishes encoding and decoding mappings, significantly reducing computational overhead. Extensive experimental results demonstrate that LuminaLink achieves an average bit-error-rate (BER) of 0.030 at the designated position, while maintaining an average BER of 0.524 at other positions, confirming its effectiveness in securing VLC communications.