Physical-layer Security in Visible Light Communications: Fundamental Theories, Key Techniques, and Future Challenges

WANG Jinyuan; YAN Xinrun; LIN Zihan; LI Yuanyuan; LI Zheng; ZHANG Xin

doi:10.11999/JEIT260338

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WANG Jinyuan, YAN Xinrun, LIN Zihan, LI Yuanyuan, LI Zheng, ZHANG Xin. Physical-layer Security in Visible Light Communications: Fundamental Theories, Key Techniques, and Future Challenges[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT260338

Citation:

WANG Jinyuan, YAN Xinrun, LIN Zihan, LI Yuanyuan, LI Zheng, ZHANG Xin. Physical-layer Security in Visible Light Communications: Fundamental Theories, Key Techniques, and Future Challenges[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT260338

Citation:

WANG Jinyuan, YAN Xinrun, LIN Zihan, LI Yuanyuan, LI Zheng, ZHANG Xin. Physical-layer Security in Visible Light Communications: Fundamental Theories, Key Techniques, and Future Challenges[J]. Journal of Electronics & Information Technology. doi: 10.11999/JEIT260338

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Physical-layer Security in Visible Light Communications: Fundamental Theories, Key Techniques, and Future Challenges

doi: 10.11999/JEIT260338 cstr: 32379.14.JEIT260338

School of Communication and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210003, China

Funds: National Natural Science Foundation of China (No. 62472233)

Received Date: 2026-03-25
Accepted Date: 2026-05-15
Rev Recd Date: 2026-05-15

Available Online: 2026-05-29

Abstract

Abstract

Significance Due to the broadcast nature of optical signals, information security represents a critical research direction in visible light communication (VLC). Conventional encryption techniques address network security issues at the upper layers of the protocol stack through access control, cryptographic protection, and end-to-end encryption. However, their security relies on the assumption that eavesdroppers possess limited computational capabilities, an assumption that currently faces significant challenges. In recent years, physical layer security (PLS) has emerged as a novel information security paradigm and has attracted considerable attention from researchers worldwide. PLS exploits the randomness, heterogeneity, and distinctiveness between the main channel and the eavesdropping channel to achieve secure information transmission at the physical layer. To date, extensive research achievements have been made regarding PLS techniques in conventional radio frequency wireless communications (RFWC). Nevertheless, due to substantial differences in frequency bands, transmitted signals, power representations, and channel characteristics, PLS research results from RFWC systems cannot be directly applied to VLC. Although scholars worldwide have conducted research on VLC PLS technology, the foundational theories, key techniques, and future challenges involved in VLC PLS still lack a systematic review. To bridge this gap, this paper presents a comprehensive survey of VLC PLS technology. Progress To evaluate and enhance system performance, a classic VLC PLS system model—comprising the received signal model, the input constraint model, and the channel gain model—is initially established. A comprehensive theoretical framework for performance evaluation is then developed, encompassing instantaneous performance metrics, statistical performance metrics, and asymptotic performance metrics. Specifically, to characterize instantaneous performance, existing works on instantaneous secrecy capacity and instantaneous secrecy rate across different scenarios are summarized. As statistical performance metrics, average secrecy capacity, average secrecy rate, secrecy outage probability, probability of strictly positive secrecy capacity, and interception probability are analyzed. To demonstrate asymptotic performance, secrecy diversity order and secrecy degrees of freedom are derived. Furthermore, to enhance the PLS performance, advanced technologies, including secure beamforming, artificial noise, physical region protection, secure coding, and secure diversity, are summarized. Prospects Despite existing research achievements, numerous challenges remain in VLC PLS. This paper identifies four critical challenges: (i) Accurate PLS performance limit: Deriving exact expression of secrecy capacity under VLC's unique physical constraints remains challenging. (ii) Incomplete evaluation framework: Some key metrics widely used in RFWC have not been investigated in VLC, and the construction of a comprehensive VLC PLS performance evaluation framework remains unresolved. (iii) Limitations of existing methods: Conventional PLS performance enhancement methods typically adopt a “modeling-optimization-verification” separated research paradigm, often falling into a vicious cycle of “inaccurate modeling-suboptimal solutions-limited performance gains”. Therefore, it is imperative to integrate novel technologies (such as deep learning, reinforcement learning, and digital twins) to construct a data-model dual-driven framework for VLC PLS performance enhancement. (iv) Hardware platform gap: The absence of dedicated hardware platforms featuring adversarial topologies and real-time processing capabilities significantly impedes the practical deployment of VLC PLS technologies. Therefore, addressing these challenges is essential for transitioning VLC PLS from theoretical advances to commercial applications. Conclusions The broadcast nature of optical signals renders VLC systems vulnerable to eavesdropping attacks. This paper presents a comprehensive survey of PLS in VLC, covering system models, performance metrics (instantaneous, statistical, and asymptotic), and key performance enhancement technologies including secure beamforming, artificial noise, physical region protection, secure coding, and secure diversity. Despite significant progress, challenges remain in establishing accurate performance bounds, complete evaluation frameworks, novel enhancement techniques, and practical hardware implementations. By exploiting channel disparities at the physical layer without relying on complex encryption, PLS represents a paradigm shift in security assurance, paving the way for next-generation secure and reliable VLC networks.
- visible light communication,
- physical-layer security,
- performance evaluation,
- performance enhancement.

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References(76)

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