Quantum Selective Encryption for Medical Images

To trade security off for computational complexity, Selective Encryption (SE) in Image Processing denotes an approach which is capable of encrypting an image partially. In other words, it is aimed at turning the visually most important parts of images into meaningless ones, ignoring unimportant regions to have a computationally-efficient technique. Based on BRQI images, in this paper, a novel quantum selective encryption method for medical images is investigated. ROI (Region of Interest) tends to be the most vital part of medical images, which should be protected during the transmissions. The proposed method encrypts this region effectively by manipulating the bitplanes of the images according to a key. Experimental results encompassing correlation of adjacent pixels, histogram analysis and entropy rate analyzed in MATLAB environment demonstrate a good performance. Furthermore, regarding a BRQI image of 2n pixels, the time complexity is not more than O(m), where m is length of the key sequence. On no condition does it depend on size of images, bringing about being far more time-efficient compared to its classical counterpart and even earlier studied works found in the literature (full-encryption ones). To the best of our knowledge, this is the first method to introduce a quantum selective image encryption method.