Statistical Analysis of Encryption Quality for Medical Images Based on Rijndael Encryption Algorithm Using Both Static and Chaotic Cipher Key

Growing application of medical information systems and various digital communication channels to transfer and share vital and medical information demonstrate the significance of medical data security and privacy policy. Nowadays several block cipher encryption algorithms secure information have done by encrypting them. Most of these algorithms are based on a block cipher that use a predetermined fixed/constant key with at least 128 bits length. In this study encryption performed by Rijndael encryption algorithm using conventional constant and variable cipher key. Mackey Glass, known as chaotic system, attached in key expansion block of Rijndael and play role in place of its conventional key expansion procedure. Mackey Glass generates series of chaotic cipher key, monitored and modified by controlling block. Both methods were evaluated by 6 individual criteria. Results have shown that variable chaotic keys are significantly successful to hide medical image pattern and histogram distribution with 2.47 percent increase in computational time where conventional Rijndael failed. Moreover this modification does not lead to considerable changes in sensitivity. Employing chaotic system in Rijndael key expansion block for medical images improves security of medical information and privacy policy.