A novel cross cosine map based medical image cryptosystem using dynamic bit-level diffusion

Development in networking technology has made the remote diagnosis and treatment of patients a reality through telemedicine. At the same time, storing and transmitting medical documents over an insecure network has always been a daunting challenge. Literature shows that the existing medical image cryptosystems suffer from serious shortcomings. The present work attempts to address this crucial area and propose a suitable solution. A novel hybrid 2-Dimensional Cross Cosine Map (2D-CCM) with an improved chaotic behaviour cryptosystem is proposed. Chaotic series generated by proposed 2D-CCM is utilized in confusion and diffusion architecture. A new dynamic Bit-Flipping in diffusion approach increases the complexity to achieve good encryption results. Simulation and security level assessment is carried out by executing Statistical and differential attack analysis, key sensitivity and exhaustive attack analysis. Robustness is evidenced by the result of noise and crop attack analysis. In addition, SHA-256 is utilized to feed the seed key value of 2D-CCM to resist plaintext attacks. All the assessment and comparison results illustrate that the cipher possesses enhanced security and efficiency than the existing state of the art. Hence the proposed cipher is absolutely apt for secure medical image communication.