Color image encryption combining a reality-preserving fractional DCT with chaotic mapping in HSI space

Chaos is widely used in secure communication and cryptography due to its randomness, unpredictability, non-periodicity and high sensitivity to initial values and parameters. However, there are many risks in some existing chaotic image encryption algorithms because they use the the chaotic map without complex dynamic characteristics. To overcome these weaknesses, in this paper introduced an improved Hénon map, and the dynamic analysis results show that the improved Hénon map has more rich chaotic behaviors and better complexity. In addition, we designed a color image encryption scheme using the improved Hénon sequences. For this encryption algorithm, color image is divided into R, G, B primary colors, then R, G, B primary colors are scrambled and diffused by the improved Hénon sequences. The simulation results illustrate that color image encryption algorithm security is advanced by usingimproved Hénon map.

A color image encryption and decryption scheme based on extended DNA coding and fractional-order 5D hyper-chaotic system

A novel color image encryption algorithm based on a cross 2D hyperchaotic map is proposed in this paper. The cross 2D hyperchaotic map is constructed using one nonlinear function and two chaotic maps with a cross structure. Chaotic behaviors are illustrated using bifurcation diagrams, Lyapunov exponent spectra, phase portraits, etc. In the color image encryption algorithm, the keys are generated using hash function SHA-512 and the information of the plain color image. First, the color plain image is converted to a combined bit-level matrix and permuted by the chaos-based row and column combined cycle shift scrambling method. Then, the scrambled integer matrix is diffused according to the selecting sequence which depends on the chaotic sequence. Last, decompose the diffusion matrix to get the encrypted color image. Simulation experiments and security evaluations show that the algorithm can encrypt the color image effectively and has good security to resist various kinds of attacks.

Images are important information carriers in our lives, and images should be secure when transmitted and stored. Image encryption algorithms based on chaos theory emerge in endlessly. Based on previous various chaotic image fast encryption algorithms, this paper proposes a color image sector fast encryption algorithm based on one-dimensional composite sinusoidal chaotic mapping. The main purpose of this algorithm is to improve the encryption and decryption speed of color images and improve the efficiency of image encryption in the big data era. First, four basic chaos maps are combined in pairs and added with sine operations. Six one-dimensional composite sinusoidal chaos maps (CSCM) were obtained. Secondly, select the two best chaotic mappings LCS and SCS. The randomness of these two chaotic mappings was verified through Lyapunov index and NIST SP 800-22 randomness tests. Thirdly, the encryption process is carried out according to the shape of a traditional Chinese fan, and the diffusion and scrambling of each pixel of the image are performed in parallel. This greatly improves encryption speed. When diffusing, changing the value of one pixel can affect the values of multiple subsequent pixels. When scrambling, each pixel changes position with the three pixels before it according to the chaotic sequence. Finally, through many experiments, it is proved that the image encryption algorithm not only greatly improves the encryption and decryption speed, but also improves various indexes. The key space reached 2192, the average information entropy was 7.9994, the average NPCR was 99.6172, and the average UACI was 33.4646. The algorithm can also resist some common attacks and accidents, such as exhaustion attack, differential attack, noise attack, information loss and so on.

In this paper, a cellular neural network (CNN) chaotic system is constructed and the multiple stability of the system and its rich chaotic properties are confirmed by studying the effect of parameters on the system, coexisting attractors, and offset boosting behavior. As linear feedback shift registers (LFSR) can be applied to cryptography, this paper applies LFSR to generate encrypted key matrices to enhance the randomness of encryption algorithms. Based on CNN and LFSR, a new color image encryption algorithm is designed by combining DNA coding and bit-plane decomposition with high bit-plane Zigzag dislocation changes. Experimental results and security tests show that the algorithm is highly secure and resistant to a variety of common attacks, such as differential attacks, cropping attacks, and noise attacks.

A novel chaotic image encryption algorithm based on content-sensitive dynamic function switching scheme

This paper proposes a color image encryption algorithm based on a cloud model Fibonacci chaotic system, as well as a matrix convolution operation that can protect image content effectively and safely. The algorithm combines the cloud model with the generalized Fibonacci, creating a new complex chaotic system that realizes the dynamic random variation of chaotic sequences. The chaotic sequence is used to scramble the pixel coordinates of the mosaic images of the R, G, and B components of the color image. Then, the chaotic sequence value is used as a matrix convolution cloud algorithm that alternately updates the input value of the matrix convolution operation and the pixel value to obtain the permutation transformation of the original pixel value. Finally, the pixel values of the replacement and cloud model Fibonacci chaotic sequence and the pixel values of the front (rear) adjacent pixel points are subjected to a two-way exclusive XOR operation. Realizing the change of the arbitrary pixel value causes a chain transformation of the pixel values of all of the pixel points, and sequentially generates an encrypted image. Experiments show that the histogram of the encrypted image is smoother and adjacent pixels of the image have low correlation. In addition, this algorithm can resist attack experiments such as differential attack, select plaintext attack and noise attack and provides high encryption security, high anti-interference, and strong robustness. The dynamic chaotic system is used to realize the color image encryption of the dynamic key, and the encryption algorithm has higher security and the validity of the algorithm.

Color image encryption has enticed a lot of attention in recent years. Many authors proposed a chaotic system-based encryption algorithms for that purpose. However, due to the shortcomings of the low dimensional chaotic systems, similar rule structure for RGB channels, and the small keyspace, many of those were cryptanalyzed by chosen-plaintext or other well-known attacks. A Security vulnerability exists because of the same method being applied over the RGB channels. This paper aims to introduce a new three-channel three rules (3C3R) image encryption algorithm along with two novel mathematical models for DNA rule generator and bit inversion. A different rule structure was applied in the different RGB-channels. In the R-channel, a novel Block-based Bit Inversion (BBI) is introduced, in the G-channel Von-Neumann (VN) and Rotated Von-Neumann (RVN)- based 2D-cellular structure is applied. In the B-channel, a novel bidirectional State Machine-based DNA rule generator (SM-DNA) is introduced. Simulations and results show that the proposed 3C3R encryption algorithm is robust against all well-known attacks particularly for the known-plaintext attacks, statistical attacks, brute-force attacks, differential attacks, and occlusion attacks, etc. Also, unlike earlier encryption algorithms, the 3C3R has no security vulnerability.

A novel image encryption algorithm based on SPWLCM and DNA coding

Security of image data is essential during communication from various security attacks. This paper proposed a new technique for RGB color image encryption and decryption by the combination of shuffling and masking. The chaotic Baker map is used for first layer of image encryption by randomizing the pixels of each components of color image such as red, green and blue and then applying the diffusion process i.e. fractional dual random phase masks (FDRPM) technique which is applied on each component to increase the security level of given method. The order of Discrete Fractional Fourier Transform (DFRFT) act as a key for the process which provides extra degree of security to the proposed system. Matlab simulations are performed to check the security robustness of proposed scheme. Performance of proposed scheme is verified by noise analysis such as mean square error (MSE) and various differential analysis such as Unified Average Change Intensity (UACI) and Number of Pixels Change Rate (NPCR). Results of various analysis shows that the novel proposed encryption technique shows high efficiency and security for color images.

In order to ensure the security of the encryption result and increase the speed of the encryption algorithm as much as possible, this paper proposes an efficient color image encryption algorithm based on 2D Sine-Logistic-Gaussian coupled chaos(2D-SLG chaos) and multi-objective optimized S-box. Firstly, this paper designs a 2D-SLG chaos to balance the complexity and computational cost of chaotic behavior. Secondly, this paper uses multi-objective particle swarm optimization to optimize the initial S-box to obtain an S-box with higher and balanced performance to perform the substitution operation. Finally, this paper uses the layer blending method to enhance the mutual influence between layers and uses the idea of linear congruence to generate permutation sequences to perform row and column shift operations. Experimental results show that the proposed encryption algorithm has excellent performance in key space, statistical analysis, key sensitivity, adjacent pixel correlation, differential attack, select plaintext attack and other security tests, and has high robustness and fast encryption speed. Therefore, the algorithm can meet the requirements of reliability and efficiency while ensuring strong security.

This paper presents a new 4D chaotic system by extending a 3D system to investigate chaotic systems2 with hidden attractors further and explore their engineering applications in color image encryption. The system has hyperbolic shape equilibriums and the equilibriums are nonhyperbolic which is interesting and rarely mentioned before. The system has been investigated deeply by phase plot, time series, the largest Lyapunov exponent, bifurcation diagram, Poincaré map and 0–1 test. A coexisting hidden attractor has been found in this new system and the circuit simulation model of the system is built by Power Simulation (PSIM). Circuit simulation results are consistent with results of numerical simulations which verify its dynamic behavior further. Then, by combining the generalized Arnold transform with the new chaotic system, a new color image encryption algorithm has been proposed which has large key space and can encrypt either square images or nonsquare images with different size. Finally, the results of encryption experiment and security analysis prove the effectiveness of the algorithm.

3D point clouds, a new primitive representation for objects, are spreading among thousands of people through internet software. Thus, the privacy preserving problem of the 3D point cloud should be widely concerned by more and more people. To ensure the safe transmission and use of point cloud, two schemes of encryption have been proposed by using chaotic cat mapping in this paper. The two encryption schemes are tested by using various types of 3D point clouds. In addition, these proposed encryption algorithms are analyzed through key space, sensibility, statistical and encryption time analysis. These analysis results show that the two proposed schemes can resist the common existing cipher attacks and are effective encryption methods for 3D point cloud encryption. At the same time, the two promising encryption algorithms can guarantee the security of the 3D point cloud model transmitted on the Internet.

In order to ensure the basic security of wireless sensor networks (WSNs), a block encryption algorithm based on chaotic substitution box (S-box) is proposed. In this paper, we generated a new S-box based on the compound chaotic map, sinusoidal chaotic map, Baker map, and linear congruence generator. In addition, the limited computing power and communication capability of WSN are also considered in this paper. The method of generating round subkeys and F function is constructed based on the S-box. The extensive security and performance tests show that the proposed encryption algorithm has high security and low resource consumption which is suitable for WSN.

Image encryption algorithm with random scrambling based on one-dimensional logistic self-embedding chaotic map