Symmetric Cryptography With Shift 2n-1, Hash Transformation, Optimization-Based Controller for Medical Image Infosecurity: Case Study in Mammographic Image

Among imaging examinations, mammography noninvasively aids in the early detection and diagnosis of diseases inside the body, such as lung cancer or breast tumor, for first-line examination and helps physicians to treat medical conditions. As digital medical images can be transmitted by computer or telecommunication network, ensuring image infosecurity in public spaces is difficult. In infosecurity considerations, digital signature and encryption of individual anamnesis plain images should prevent data from being stolen, tampered, or peeked by unauthorized people. Hence, infosecurity has become an important issue in the digital era. This study proposes right / left shift 2
^n-1
pixel values, hash transformation with multi-secret gold keys, and an optimization-based controller to integrate two symmetric cryptography processes for medical image encryption and decryption with the same secret gold keys. Then, swarm optimization-based controllers, which are based on particle swarm optimization (PSO) and firefly algorithm (FA), are implemented to search the decryption key parameters. For a case study on mammographic images consisting of medical X-ray images of 50 benign tumors and 50 malignant tumors, the peak signal-to-noise ratio is used to evaluate the relation between the original plain images and decrypted images. Conclusively, the FA-based controller performed better than the PSO-based controller in terms of recovery reliability and speeds up the computation of the desired optimal solution.