Lightweight medical-image encryption technique for IoMT based healthcare applications

One of the most demanding issues in smart healthcare systems like IoMT is the security of Electronic Health Records (EHR). In IoMT-based systems, the health record is usually collected from various sensors which are generally resource-contained. Coupled with this the critical healthcare data needs to be processed mostly in real-time to facilitate better decision-making in emergencies. This demands the need for a computationally efficient security solution for EHR in IoMT-based systems. Towards this end, we present a novel, fast, and proficient lightweight image encryption technique founded on the substitution permutation network. The network consists of two stages of the substitution process which is carried out after splitting the original image into small \(8\times 8\) $8\times 8$ blocks by performing a bitwise XOR operation using transformation magic \(8\times 8\) $8\times 8$ blocks. These magic blocks are created using various subsystems like hash function, tent-logistic system, and enhanced coupling quadratic map, and have properties like collision resistance, sensitivity to the initial control parameters, non-convergence, and ergodicity thereby making them suitable for fast and lightweight cryptosystems. In the middle of the two substitution stages, image scrambling is performed using a Tent-Logistic System. The proposed technique is examined, assessed, and compared to already existing schemes in terms of entropy analysis, differential analysis, histogram analysis, correlation coefficient analysis, key sensitive analysis, and computational time. Experimental results confirm that the proposed algorithm provides better security and robustness towards various attacks in comparison to various proposed methodologies and as such is a potential candidate for securing patient data in IoMT systems.