Quantum image encryption scheme using DPS protocol based on 3D non-equilateral Arnold transform and URUK chaotic map

There is an increasing demand for robust and secure methods to protect sensitive image data in the era of quantum computing. So, we have developed a novel quantum-inspired image encryption framework that integrates quantum bit-plane Real Ket (QBRK) decomposition, quantum bit-plane scrambling (QBPS), the URUK chaotic map, and the Differential Phase Shift (DPS) quantum key distribution (QKD) protocol over a Free Space Optics (FSO) channel. The developed model leverages QBRK-based bit-level processing to extract pixel-level quantum features, which are scrambled using the final key generated by combining the URUK chaotic map and DPS protocol. To enhance spatial diffusion, a 3D non-equilateral Arnold transform (3D NEAT) is applied to the scrambled image, followed by final encryption with a dynamically generated XOR key. The robustness of the developed scheme is validated through multiple visual and objective analysis metrics including entropy, Number of Pixel Change Rate ($NPCR$), Unified Average Changing Intensity ($UACI$), Peak Signal-to-Noise Ratio ($PSNR$), Fourier spectrums, Quantum Bit Error Rate (QBER), fidelity, and eavesdropping detection probability. Simulation results confirm that the designed technique ensures high security, strong randomness, and resistance against quantum eavesdropping, even under noisy FSO transmission environments. The proposed quantum encryption approach demonstrates the potential for secure and efficient image protection in next-generation quantum communication systems. The suggested algorithm is validated using the OptiSystem 15.1 software under the FSO channel. The efficacy of the developed encryption scheme is corroborated against various recently developed encryption methods and found to be effective.