Lightweight Hybrid Chaotic Image Encryption With Spiral Shuffling and S‐Box Diffusion
Dipankar Dey, Prajna Bhunia, Dipak Kumar Jana, Sudip Diyasi, Supriya Maity · Security and Privacy · 2025
ABSTRACT We propose an adaptive chaotic image encryption scheme that integrates spiral pixel shuffling, chaos‐driven dynamic S‐box substitution, and hybrid chaotic diffusion. The design employs a coupled logistic–tent map with golden‐ratio perturbation, expanding the key space to approximately , where the exponent denotes the effective size. This hybrid approach addresses limitations of existing schemes—such as restricted randomness, vulnerability to differential attacks, and impractical runtime for real‐time applications—while maintaining low computational complexity suitable for IoT and medical contexts. Comprehensive evaluations confirm strong security: NPCR , UACI , entropy , and near‐zero pixel correlation, demonstrating resistance to statistical, differential, and chosen‐plaintext attacks. Side‐channel leakage simulations further show stable per‐pixel timing in the microsecond range and consistent power traces, indicating robustness against timing and power analysis, with future hardware validation planned. The proposed scheme achieves an average encryption time of 43.97 s and decryption time of 32.26 s for color images, confirming suitability for real‐time image processing. These results position the proposed method as a lightweight, secure, and practical framework for protecting medical data, multimedia content, and IoT edge devices.