Lightweight Biomedical Image Encryption Approach

This paper proposes a lightweight image encryption approach for medical Internet of Things (MIoT) networks using compressive sensing and a modified seven-dimensional (MSD) hyperchaotic map. Initially, 7D hyperchaotic map is modified to generate more secure and complex secret keys. SHA-512 is used to create the initial conditions for MSD, which ensures its sensitivity towards input images. Using nonsubsampled contourlet transform (NSCT), further improvements in the compressive sensing are achieved, and then the measurement matrices are generated using the secret keys obtained from MSD. Finally, to generate encrypted images, the diffusion and permutation are carried out row and column-wise on compressed images using secret keys obtained from MSD. The comparative analyses verify the performance of the proposed lightweight encryption approach in terms of robustness, security, and statistical analysis.