A dynamic approach for a lightweight and secure cipher for medical images

Abstract

Protecting the contents of medical records is of paramount importance when it comes to preserving patients' privacy. Most existing cryptographic-based solutions rely on traditional encryption algorithms having a multi-round structure, which introduces processing latency and requires increased resources. Medical images possess special characteristics compared to other types of images. The main goal of this paper is to leverage these characteristics to design and implement an efficient and secure encryption algorithm for such images. The proposed solution defines three variants of encryption algorithms: (a) full, (b) middlefull, and (c) selective. The full approach encrypts all sub-matrices of an image, while the middle-full variant is a middle solution between the selective and full algorithms and its goal is to just hide the type of the medical image. Selective encryption identifies a set of sub-matrices of an image according to a statistical average test, known as region of interest (ROI). In the three approaches, a high security level is ensured since each image is encrypted independently of the previous and next images. Also, all primitives of the proposed cipher, such as permutation and substitution, depend on a dynamic key. Furthermore, the encryption scheme is efficient since the proposed round function is lightweight and applied for only one round. This reduces the latency and the required resources as compared to traditional cryptographic schemes. The proposed approach is flexible as it can be applied in either selective, middle-full, or full mode. Also, the size of a sub-matrix is variable and can be changed according to the available memory size. Several security and performance tests are conducted to evaluate the effectiveness of the proposed solution. The results validate the robustness of the proposed scheme against almost all considered types of attacks and show an improvement in terms of latency and resources compared to current image-encryption schemes. Also, the results confirm the robustness of the proposed algorithm in protecting the contents of medical images.

When an attacker meets a cipher-image in 2018: A year in review

“…Due to the large size of conventional image files, compression and encryption should be combined well [92,134]. As [135], only ROI (region of interest) of DICOM (Digital Imaging and Communications in Medicine) medical images are encrypted with one round of permutation and substitution to satisfy real-time processing requirement.…”

A Novel Lossless Medical Image Encryption Scheme Based on Game Theory With Optimized ROI Parameters and Hidden ROI Position

“…Therefore, our encryption algorithm can better protect the integrity of image information, and is more suitable for medical image encryption or other encryption fields that require high image integrity. At the same time, the image information is further hidden due to changes in the image format [8].…”

“…However, in wireless medical networks and mobile medical services, information processing requires timely, mobile medical equipment and wireless network equipment have limited computing power and are constrained by electrical energy reserves. So traditional full encryption schemes are not suitable for medical image encryption [8].…”

“…Artificial neural networks (ANN) are applied to the detection of regions of interest (ROI), and a kind of solution for automatically selecting ROI regions is given in [16]. There are other excellent solutions to choose the privacy regions automatically, such as threshold segmentation, face detection, infrared targeting, and salient mapping [8], [17], [18]. However, most of the above schemes are affected by the fixed segmentation threshold and the fixed detection parameters, and cannot automatically adapt to the images with different structures and formats.…”

TRESC: Towards redesigning existing symmetric ciphers

“…The attackers would try to recover the secret key given that the static ciphers use fixed cryptographic primitives [14]. Thus, dynamic lightweight cipher schemes are required to strike the balance between security and performance [15], [16], [17], [18], [19], [20].…”