A new improved three-dimensional continuous chaotic system (ImproBsys) is designed in this paper. It can achieve from an ordinary chaotic state to a hyperchaotic state, that is, chaotic behavior tends to become more complex. Furthermore, by using ImproBsys, this paper proposes a double image encryption algorithm based on compressive sensing and public key elliptic curve. First, the two plain images of the same size are excuted by discrete wavelet transformation (DWT), and then the DWT coefficients are thresholded. Second, the quantization matrix is compressed by compressive sensing, and the size is reduced to half of the original one, and then the two compressed matrices are spliced together to form a new matrix. Finally, the new matrix is encrypted by elliptic curve cipher to get the cipher image. Our contributions are: (1) A new ImproBsys is designed with better chaotic behavior, which has two positive Lyapunov exponents to show hyperchaos phenomenon. (2) Compressive sensing technique is employed to reduce the amount of data transmission for two single images, and then we use ImproBsys to control the measurement matrix. (3) The initial values of the ImproBsys depend on the information entropy of the plain image by a new constructed mathematical model. 

Double image encryption algorithm based on compressive sensing and elliptic curve

Hyperchaotic memristive ring neural network and application in medical image encryption

https://link.springer.com/content/pdf/10.1007/s12652-021-03675-y.pdf

Novel encryption for color images using fractional-order hyperchaotic system

Audio information strongly correlates in adjacent times, and the data type of the audio is float, so the traditional encryption algorithms for the image are unsuitable for audio encryption. This paper proposes an audio encryption algorithm based on Chaos, named AEA-NCS. Most 1D maps have a control parameter, and the parameter space in the chaotic state is small. Therefore, a 2D-Logistic-nested-infinite-collapse (2D-LNIC) is proposed by combining an infinite collapse map (1D-ICM) and a logistic map. There are two control parameters in 2D-LNIC, and it exhibits good chaotic performance through the Lyapunov exponent and attractor phase diagram . In the audio encryption algorithm, 2D-LNIC generates the keystream, and the encryption algorithm is a process of scrambling and diffusion simultaneously. This structure increases the security of the algorithm. We evaluate AEA-NCS in ESC-50, and the evaluation results show that AEA-NCS exhibits good performance, significantly reducing the correlation of audio information in adjacent times. • A 2D-LNIC is proposed and its dynamic behavior is analyzed. • An audio encryption algorithm, named AEA-NCS is proposed based on 2D-LNIC. • Experimental analysis show that AEA-NCS exhibits good performance. 

AEA-NCS: An audio encryption algorithm based on a nested chaotic system

With the advancements in e-healthcare services, it is possible to provide remote medical services to patients and swifter first aid. Medical images play an essential role in e-healthcare applications for providing quick and better remote diagnosis and treatment to patients. Medical images generally comprise secret details about the patients and are therefore prone to various security threats during their transmission over public networks. Thus, it is required to secure these images prior to their communication over public networks. But due to distinctive properties of medical images, like higher correlation and redundancy among the pixels, and larger size, it is required to design an efficient encryption model to resist against various security threats. In this paper, an efficient encryption model for medical images is proposed. To obtain the secret keys, six-dimensional hyperchaotic map (SDHM) is proposed. Firstly, plain medical image is divided into three channels such as red, green, and blue. Secret keys are used to diffuse these channels. Lastly, encrypted channels are concatenated and final encrypted medical image is obtained. Extensive experiments are drawn by considering the benchmark medical images. Also, comparisons are performed among the proposed SDHM and competitive techniques by considering various performance metrics. Comparative analysis reveals that the proposed SDHM achieves remarkably good performance than the existing encryption models.

/pdf/securing-e-healthcare-images-using-an-efficient-image-j8fvwnjo.pdf

Securing E-Healthcare Images Using an Efficient Image Encryption Model

Recently, diagnosing diseases using medical images became crucial. As these images are transmitted through the network, they need a high level of protection. If the data in these images are liable for unauthorized usage, this may lead to severe problems. There are different methods for securing images. One of the most efficient techniques for securing medical images is encryption. Confusion and diffusion are the two main steps used in encryption algorithms. This paper presents a new encryption algorithm for encrypting both grey and color medical images. A new image splitting technique based on image blocks introduced. Then, the image blocks scrambled using a zigzag pattern, rotation, and random permutation. Then, a chaotic logistic map generates a key to diffuse the scrambled image. The efficiency of our proposed method in encrypting medical images is evaluated using security analysis and time complexity. The security is tested in entropy, histogram differential attacks, correlation coefficient, PSNR, keyspace, and sensitivity. The achieved results show a high-performance security level reached by successful encryption of both grey and color medical images. A comparison with various encryption methods is performed. The proposed encryption algorithm outperformed the recent existing encryption methods in encrypting medical images.

/pdf/a-new-image-encryption-algorithm-for-grey-and-color-medical-32ei2wr5al.pdf

A New Image Encryption Algorithm for Grey and Color Medical Images

In the age of Information Technology, the day-life required transmitting millions of images between users. Securing these images is essential. Digital image encryption is a well-known technique used in securing image content. In image encryption techniques, digital images are converted into noise images using secret keys, where restoring them to their originals required the same keys. Most image encryption techniques depend on two steps: confusion and diffusion. In this work, a new algorithm presented for image encryption using a hyperchaotic system and Fibonacci Q-matrix. The original image is confused in this algorithm, utilizing randomly generated numbers by the six-dimension hyperchaotic system. Then, the permutated image diffused using the Fibonacci Q-matrix. The proposed image encryption algorithm tested using noise and data cut attacks, histograms, keyspace, and sensitivity. Moreover, the proposed algorithm’s performance compared with several existing algorithms using entropy, correlation coefficients, and robustness against attack. The proposed algorithm achieved an excellent security level and outperformed the existing image encryption algorithms.

New Image Encryption Algorithm Using Hyperchaotic System and Fibonacci Q-Matrix

Images are very important forms of data that are widely used nowadays. Every day, millions of grey and color images are transferred via the web. Protecting these images from unauthorized persons is an important issue. Image encryption is one of the image-securing techniques. One advantage of using encryption is that the plain image is converted to an unrecognized one. Also, the plain image is restored without any loss of information. In this paper, a color image encryption technique using blocks scrambling and chaos is presented. First, the plain image is decomposed into three channels: R, G, and B. Then, each channel is divided into sub-images and blocks. Our encryption algorithm depends on two main steps: scrambling and diffusion. First, the pixels’ arrangement in sub-images and blocks is changed, and then scrambling between sub-images is done to get the scrambled image. Then, in diffusion, the scrambled image diffuses using the logistic map to get the encrypted image. The experimental results show that our proposed algorithm has good performance in encrypting color images.

Sara T. Kamal

Papers

A New Image Encryption Algorithm for Grey and Color Medical Images

New Image Encryption Algorithm Using Hyperchaotic System and Fibonacci Q-Matrix

A color image encryption technique using block scrambling and chaos

Novel encryption for color images using fractional-order hyperchaotic system

A novel color image encryption based on fractional shifted Gegenbauer moments and 2D logistic-sine map