Enhanced RC6 permutation-diffusion operation for image encryption

RC6 is considered one of the encryption strategies being utilized and modified to be suited for image protection. However, the RC6 encryption algorithm is still prone to statistical and differential attack which is one of the major concerns whenever open networks are to be used. In this paper, we proposed a modification of RC6 algorithm for image encryption. A new technique of permutation-diffusion architecture based on a modified concept of cyclic shift is integrated to increase the degree of permutation and diffusion mechanism of RC6 for image encryption. The security level, processing time and diffusion rate were tested using image evaluation metrics such as correlation coefficient test, number of pixel change rate (NPCR) test, unified average change intensity (UACI) test, and run-time analysis to measure its efficiency along with the simulation process. Results show that the proposed method illustrates a lower value of correlation among pixels and higher value of NPCR and UACI which makes the proposed method highly resistant to statistical and differential attacks. Increased security level with minimal time consumption is achieved in our approach.