Image Encryption Approach Based on Quad-Tree and PRESENT Algorithm

In today's world, data transmission and storage are becoming increasingly dependent on information security, and many processes frequently employ images. Therefore, it is essential to protect image data against unwanted access. For this purpose, the Quad-tree decomposition technique is employed with the PRESENT algorithm. The proposed technique encrypts the color images completely by splitting an image utilizing the Quad-tree decomposition technique depending on the variance of the blocks in the image. Then, encryption is carried out. The image blocks with homogenous pixel levels are treated as unimportant blocks (regions) and others are important. Then, the pixels in the important blocks are encrypted using the PRESENT algorithm after some change by running more rounds of s-box and permutation layer on them and fewer rounds on the insignificant blocks to balance the complexity. The suggested method produces good results for image encryption on statistical attacks. When compared to current encryption techniques, the results are close to the optimal value and ensure images security. The experimental results indicate that the proposed scheme can successfully encrypt the images, and the algorithm analysis also shows that the encrypted image has good entropy and low correlation coefficients, therefore satisfying the required protection.