Today’s technological era, the booming desire for e-healthcare has inflated the attention towards the security of data from cyber attacks. As the digital medical images are transferred over the public network, there is a demand to shield an adequate level of protection. One of the prominent techniques is encryption which secures the medical images. This paper recommends a DICOM image encryption based upon chaotic attractors on frequency domain by integer wavelet transform (IWT) and fused with deoxyribonucleic acid (DNA) sequence on the spatial domain. The proposed algorithm uses a chaotic 3D Lorenz attractor and logistic map to generate pseudo-random keys for encryption. The algorithm involves subsequent stages, i.e. permutation, substitution, encoding, complementary and decoding. To endorse the resistance of the proposed algorithm, various analyses have been examined for 256 × 256 DICOM images by achieving an average entropy of 7.99, larger keyspace of 10238 and non-zero correlation. The overall results confirm that the proposed algorithm is robust against the brute force attacks.

A robust medical image encryption in dual domain: chaos-DNA-IWT combined approach

A digital image encryption algorithm based on dynamic deoxyribonucleic acid coding and chaotic operations using hyper digital chaos in frequency-domain is proposed and demonstrated, where both the amplitude and phase components in frequency-domain are diffused and scrambled. The proposed encryption algorithm is evaluated through various evaluations of key parameters such as histogram uniformity, entropy, and correlation. Excellent performance of the encrypted image is achieved to resist the statistical attacks, which implies that the statistical properties of the original image are completely destroyed. In the encryption procedure, each cipher pixel is affected by all of the plain-pixels as well as cipher-pixels, due to the implementation of chaotic diffusion and scrambling operations, which increases the sensitivity of the encrypted image to the plain-text, and improves the security against any differential attacks. Moreover, due to the high sensitivity introduced by the hyper digital chaos, a huge key space is provided for the encrypted image to ensure the high security level, thus the encryption algorithm has a strong secure capability against the brute-force attacks.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-ipr.2019.0051

Chaotic image encryption algorithm using frequency-domain DNA encoding

One of the applications of dynamical systems with chaotic behavior is data encryption. Chaos-based cryptography uses chaotic dynamical systems as the basis for creating algorithms. The present article discusses a new dynamical system called M-map with its analysis: fixed points, bifurcation diagram, Lyapunov exponent, and invariant density. The obtained bifurcation diagram and the plot of the Lyapunov exponent (with a minimum value of ln2 and a maximum value of ln4) suggest that the so-called robust chaos characterizes this map. Moreover, the obtained results are compared with other dynamical systems used in cryptography. Additionally, the article proposes a new image encryption algorithm. It uses, among others, cyclically shifted S-box or saving encrypted pixels on the first or last free space in the cipher-image. The conducted analysis shows that the cipher-images are characterized by an entropy value close to 8, a correlation of adjacent pixels value close to 0, or values of Number of Pixel of Change Rate (NPCR) and Unified Average Changing Intensity (UACI) measures close to 100% and 33%, respectively.

https://www.mdpi.com/2073-8994/14/5/895/pdf?version=1651109697

New Chaotic System: M-Map and Its Application in Chaos-Based Cryptography

Nowadays, digital image communication through internet has become essential in public network as images can give a clear vision than describing something through text. Data such as medical images, military images, etc. which are highly prone to intruders are mandatory to be maintained confidential to transmit and receive data safely without being intruded by unauthorised persons. This technique can be provided by encrypting these digital images through cryptographic techniques. The proposed image encryption is performed in the transform domain, where Integer Wavelet Transform is adopted to separate the image into approximation coefficients and detailed coefficients. In IWT, most of the significant pixels are in the low-frequency band where confusion and diffusion is performed with chaotic logistic keys. The experimental results achieved entropy of 7.97 and near-zero correlation to verify it is able to resist any statistical attacks.

Implementation of Image Encryption based on Chaos-IWT– An Image security

The increase of cyberattacks in the field of information security leads to high attention in the digitalized environment. There is a demand for well-organised methods to transmit data securely over the Internet. In the proposed algorithm, a greyscale image is secured by an encryption technique by two stages, i.e. confusion and diffusion. Digital images can be expressed in terms of numeric values called pixels. The images are converted by the integer wavelet transform-domain technique, where the images are separated by approximation and detailed sub-bands. The proposed encryption algorithm is implemented for the approximated sub-bands which contain significant information of the digital image. 1D logistic and 2D tent maps generate chaotic random keys. By various statistical and differential analyses, the robustness of the proposed algorithm is examined by achieving a maximum entropy of 7.997, near-zero correlation and larger keyspace of 1080. With the results, it has confirmed that the enhanced chaos-based Integer Wavelet Transform (IWT) encryption has succeeded to resist any cyberattacks.

Robust Image Encryption in Transform Domain Using Duo Chaotic Maps—A Secure Communication

Secure transmissions of secret images over the public network have a lot of challenges that include hacking, manipulating the actual content, destroying, etc. In order to solve these issues, various image encryption algorithm has been given by experts that work on both spatial or frequencies domain. Most of them are work with gray scale images. In this paper, a robust color image encryption technique is proposed that uses Discrete Cosine Transformation (DCT) and a diffusion operation first applied in spatial domain and then a confusion operation is applied in frequency domain, and that's why this paper has title in dual domain. In encryption, firstly the plain image is performed the XOR operation with key generated by Logistic Map, and we get the diffused image of plain image. Then diffused image is divided into fixed-size blocks and converted in frequencies domain using DCT, then chaotic map is applied to reorder the frequencies coefficient. At last, the Inverse DCT (IDCT) is applied to get the encrypted image. In order to prove the algorithm robustness, various tests has been performed and its result has been compared with existing technique. The analysis and result show that the encrypted image is enough robust against any types of attacks.

Kuldeep Tomar

Papers

A Robust Color Image Encryption Algorithm in Dual Domain Using Chaotic Map