Chaotic Image Encryption Scheme Based on Improved Z-Order Curve, Modified Josephus Problem, and RNA Operations: An Experimental Li-Fi Approach

Image encryption schemes are predominantly software-based. Only a select few have been implemented in real-life communication systems. This paper introduces a novel chaotic image encryption scheme based on a modified Z-order curve, a modified Josephus problem, and an improved Vigenère cipher–based ribonucleic acid (RNA) operation. It is implemented and assessed within a light-fidelity (Li-Fi) infrastructure, comprising two core components: software and hardware. The software component manages data encryption and decryption, while the hardware ensures efficient data transmission. The proposed encryption scheme starts with a pixel-level permutation based on an improved Z-order curve, applicable to rectangular images, optimizing efficiency and increasing permutation ability. This is followed by a bit-level permutation using a modified Josephus problem, which enhances the diversity of generated sequences and introduces additional dislocation effects. Subsequently, a Vigenère cipher–based RNA operation serves for diffusion alongside basic RNA operations and the cipher block chaining (CBC) mode. Theoretical analyses and experimental findings demonstrate that the proposed encryption scheme is highly robust, outperforming several existing cryptosystems. Moreover, owing to its successful implementation, the proposed encryption scheme signifies a compelling stride toward bolstering secure visible light communication systems.