Design and performance of entanglement-based underwater VLC/QKD systems

Underwater wireless communication is rapidly advancing, finding applications in diverse fields such as oceanography, defense, and commercial ventures. However, ensuring security in such transmissions is crucial due to the sensitive nature of the data involved and the challenges posed by the underwater environment. While classical encryption techniques provide some level of security, the emergence of quantum computing presents opportunities and challenges. Quantum key distribution (QKD) offers theoretically unbreakable encryption, making it an attractive solution. Extending QKD capabilities to underwater environments is a significant endeavor in this context. This paper explores the feasibility of applying an entanglement-based non-coherent QKD protocol inspired by the BBM92 protocol to underwater visible light communication (VLC)/QKD systems. We investigate the system’s design criteria and analyze its secret key performance, addressing challenges such as water absorption and turbulence-induced fading, focusing on addressing unauthorized receiver attacks. Through analysis and the considered case study, the feasibility and efficacy of this approach are explored, contributing to the advancement of secure underwater communications.