A blockchain-integrated chaotic fractal encryption scheme for secure medical imaging in industrial IoT settings

The increasing adoption of smart cameras and image sensors in industrial and medical applications necessitates robust visual data security solutions. The industrial Internet of Things (IoT) introduces unique security challenges, particularly due to third-party involvement, which undermines traditional security mechanisms. This study presents a three-layered encryption scheme integrating novel blockchain technology with chaotic fractal image encryption scheme to address these challenges. The encryption process combines an S-box generated from the May map for pixel substitution with fractal-based key generation using a logistic map-driven Sierpinski triangle and incorporates a Chebyshev map-based diffusion step for enhanced randomness and security. Extensive testing, including key sensitivity analysis, entropy calculations (average entropy: 7.9998), NPCR (99.92%), UACI (33.31%), and PSNR values (29.74 dB for encrypted images), validates the scheme's robustness. The results confirm high resistance to differential and brute-force attacks, making the scheme highly suitable for securing sensitive medical images in IoT environments while ensuring confidentiality and integrity.