Chaotic intermittency-sawtooth map model ofaggregate self-similar traffic streams

A novel image steganography method using chaotic map and human visual model is presented in DCT domain. Firstly each 8×8 image block is performed Discrete Cosine Transform, then the location of image block that is embedded secret message is determined by the chaotic map. Finally the secret message is embedded adaptively in the usable middle frequency coefficient pairs judged by Just Noticeable Difference(JND). Simulation results show that the algorithm has a high capacity and a good invisibility, moreover it is robust for the common image processing like JPEG compression and cropping.

Gradient-based non-dominated sorting genetic algorithm II (G-NSGA-II) is successful for solving multi-objective optimization problems. However, the effectiveness of gradient-based hybrid operator is influenced by the distribution of individuals in the population. In order to solve the problem, based on the framework of G-NSGA-II, we propose an improved gradient-based NSGA-II algorithm by introducing a new chaotic map model named IG-NSGA-II. In this algorithm, a new hybrid chaotic map model is first established to initialize population for keeping the diversity of the initial population. Then, the substitution operation of chaotic population candidate is introduced to maintain the diversity and uniformity of the Pareto optimal solution set. Finally, the proposed algorithm is tested on several standard test problems and compared with other algorithms. The experimental results indicate that the proposed algorithm leads to better performance results in terms of the convergence to Pareto front or the diversity of the obtained non-dominated solutions.

A chaotic map model with infinite collapses in the finite region is proposed in this paper. The scheme of generating chaotic signals from this model is analyzed. Lyapunov exponents of the map calculated indicates that it has good properties of chaos. The CDMA spreading sequences produced by the model can achieve better autocorrelation and crosscorrelation characteristics than Gold sequences usually used.

In this paper, a discrete model of memristor is adopted and analyzed. The new discrete maps are built by introducing this discrete memristor model into a two-dimensional discrete map. Interestingly, introducing this discrete memristor model from different locations can lead to two new chaotic map models. The dynamical behaviors of the two maps are studied by means of bifurcation diagrams, phase diagrams and Lyapunov exponential spectra (LEs). The simulation results show that both chaotic systems have rich dynamical behaviors. In addition, they are experimentally found to have multi-stable properties, where the M-XM map has infinite attractors coexistence. Finally, we complete the hardware implementation of the two maps based on Digital Signal Processing (DSP) platform for the application of discrete chaotic systems.

A simplified and efficient technique of cryptography of an image will be developed. The technique will utilize two simple rounds to apply image encryption and decryption, each round will be implemented by performing a simple rows shuffling and columns shuffling, eliminating the need for computational logical and arithmetic operations required for other techniques of image encryption. Our approach, while simplifying computational demands by eliminating complex arithmetic and logical operations, maintains robust security through the integration of dual Chaotic Logistic Map Models (CLMM) to generate highly sensitive indices keys. These indices keys control row and column shuffling, which provides a high degree of permutation and resists known-plaintext and cipher text-only attacks. The technique will require two secret indices keys, these keys will be variable in the length and the contents and they will depend on the image to be encrypted-decrypted, generation of these keys will be very easy and simple. The shuffling operations will be implemented using two secret indices keys, and by implementing couple of chaotic logistic map these keys will be produced using selected chaotic parameters values included in the private key. The technique uses a 256-bit private key, chaotic logistic maps, and high sensitivity to parameter variations to achieve "Very strong" key space entropy, with encryption throughput of 19,540 KB/s and robust performance across diverse image sizes. The generated decrypted image may become so sensitive to chosen of private key values, and any little variation in the private key through the decryption task, it will be showed as a hacking try. The proposed technique will be flexible, it will be used to process every image with any size (gray and/or color), and image changing will not require any updating in the decryption and encryption processes. The developed technique will be efficient; it will decrease both the encryption and decryption times, and it lead to accelerate the image encryption process comparing with other techniques. The study systematically utilizes specific evaluation metrics to substantiate claims regarding the quality, security, and velocity of the proposed cryptographic technique. Quality is assessed by Mean Square Error (MSE) and Peak Signal-to-Noise Ratio (PSNR) metrics

Recently, due to the initial sensitivity, ergodicity, boundedness, and unpredictability of chaos, it has been widely used in the fields of secure communication, signal processing, chaotic synchronization, etc. Moreover, due to the low complexity of hardware implementation, widespread attention to one-dimensional (1D) chaotic maps has been paid from researchers. However, some existing 1D maps have simple chaotic behaviors and discrete chaotic intervals, which have significantly affected the practical application. To address these shortcomings, this paper proposes a 1D chaotic model based on the absolute value function and the cosine function called the cosine-coupled chaotic model (CCCM). It can use existing 1D chaotic maps as seed maps to construct a series of 1D chaotic maps with continuous chaotic intervals and complex chaotic behaviors. To verify the effectiveness of the CCCM, we first generate three new chaotic maps using the CCCM, and then their chaotic properties are analyzed by using various measures including Lyapunov exponent (LE), sample entropy (SE), correlation dimension (CD), 0-1 test and sensitivity. The experimental results confirm that the new chaotic maps have wider chaotic intervals and more complex chaotic behaviors than the corresponding seed maps and some other advanced chaotic maps. Then we use a field programmable gate array (FPGA) as the hardware platform for simple hardware implementations of the new chaotic maps. And a new pseudo-random number generator (PRNG) is introduced to verify practical applications of the new maps. Finally, experimental results show that the new chaotic maps can be implemented on FPGA and the proposed PRNG has strong random properties.

A novel image encryption scheme based on a 3D enhanced chaotic map and DNA computing model

An efficient and highly secure method of secret message cryptography will be presented which based on the principle of playing cards shuffling. The method will be implemented in a selected number of layers, each layer will encrypt-decrypt the input message using its own private key (PK), the output of any layer can be taken as a final encrypted-decrypted message, increasing the number of layers will increase the security level of the massage, making the hacking attacks impossible. In the encryption function a key generation and a message blocks shuffling will be executed, while in the decryption function the key generation and the message blocks reverse shuffling will be executed. The PK used in this method will be complicated and it will contain for each layer 2 chaotic parameters (r and x) and the block size (BS), utilizing these parameters, a chaotic logistic map model is run to produce a chaotic key, which is sorted to produce the layer's index key. Applying 4 layers the length of confidential key will be 768 bits, this length will be able to generate a large key space which is robust to hacking attempts. The speed parameters and throughput of the proposed will be calculated and compared with those of other methods.

Protecting digital speech files is an important issue. In this paper's research, a simplified method of speech file cryptography will be provided, and the encryption and decryption functions will require a reduced number of operations. The encryption function will perform a put_operation to reorder the speech sample to get the encrypted file, while the decryption function will perform a get_operation to reorder the encrypted samples to get the decrypted speech file; these operations will be implemented based on the generated secret indices key. The Put and get operations will affect the speech file by recording the samples keeping the histograms of the speech files (source, encrypted, and decrypted) the same and without any changes. The secret key generation phase will be analyzed for efficiency purposes, and two methods will be presented: The first one will use the chaotic logistic map model to generate the secret indices key, while the second method will use a selected secret image to generate the secret indices key, both methods will be tested and examined to give some recommendations for the users. Each of the introduced methods will provide a high level of security, the private keys will provide a huge key space and they will be very sensitive to resist any hacking attacks. The quality, sensitivity, security, and speed of the proposed methods will be examined, the method will be tested and implemented, and the obtained results will be analyzed to prove the achievements provided by the proposed method.

In this paper, the authors introduce a methodology to characterize time-dependent soot volume fraction fluctuations in turbulent diffusion flames via chaotic maps. The approach is based on the hypothesis that fluctuations of properties in turbulent flames are deterministic in nature, rather than statistical. The objective is to develop models of these fluctuations to be used in comprehensive algorithms to study the nature of turbulent flames and the interaction of turbulence with radiation. To this end the authors measured the time series of soot scattering coefficient in an ethylene diffusion flame from light scattering experiments and fit these data to linear combinations of chaotic maps of the unit interval. Both time series and power spectra can be modeled with reasonable accuracy in this way.

In this paper, a chaotic image encryption algorithm is suggested combining with double chaotic maps, SHA‐3 (Secure Hash Algorithm‐3), and auto‐updating system. To shuffle pixel positions, a matrix having same size of the plain‐image is generated dependent on the plain‐image in stage of permutation. Then, SHA‐3 is taken to calculate its hash values used to produce control parameter and initial condition of Logistic map. After that, total permutation is implemented for row and column to exchange pixels, where auto‐updating systems are established by different images acting like one‐time pad. Furthermore, 3D chaotic cat map is employed to enlarge key space in diffusion process. Permuted image is firstly divided into four sub‐blocks, which are queued randomly according to the key of Logistic map. The last sub‐block is picked out to calculate the hash values using SHA‐3, of which are assigned into three groups to update the initial conditions of 3D chaotic cat map performing like one‐time pad again. Current sub‐block is designed to influence next sub‐block in diffusion process. As a result, the proposed algorithm can resist efficiently the chosen‐plaintext and known‐plaintext attacks. Experimental results are also given to explain the high security of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd.

Recently, the application of memristors in chaotic systems has been extensively studied. Unfortunately, there is limited literature on the introduction of discrete memristors into chaotic maps, especially into non-classical multidimensional maps. For this reason, this paper establishes a new three-dimensional parabolic chaotic map model; in order to improve the complexity and randomness of the map, it is coupled with a square-charge-controlled discrete memristor to design a new four-dimensional memristive hyperchaotic map. Firstly, the stability of the two maps is discussed. And their dynamical properties are compared using Lyapunov exponential spectra and bifurcation diagrams. Then, the phase diagram and iteration sequence of the 4D memristive hyperchaotic map are obtained. Meanwhile, we investigate the hyperchaotic states, the transient chaos, state transfer and attractor coexistence phenomena of the four-dimensional memristive map. In particular, the special state transfer phenomenon of switching from a periodic attractor to a quasi-periodic attractor and the special coexistence phenomenon of a quasi-periodic attractor coexisting with a quasi-periodic attractor around fixed points are found, which have not been observed in other systems. Finally, the phase-track diagrams and iterative sequence diagrams of the four-dimensional memristive map are verified on a digital experimental platform, revealing its potential for practical applications.

the bits of the encrypted data. In (12), a method based on the chaotic model has been used. In this method, each bit of the encrypted data is hidden in the least valuable bit of a pixel of the image the position of which is determined by the chaotic model. In (13) also, a method has been introduced which is based on the histogram of the image; and in which the highest and the lowest frequency of the gray surfaces in the image are employed for hiding the bits of the encrypted data. The major difficulties in most of these presented methods can be studied under two headings: (a) the unbalanced distribution of the bits of the encrypted data on the surface of the cover image, and (b) the reduction in the hiding capacity In this paper, a new method is introduced in which the chaotic model and the histogram of the image are used. The chaotic feature of the signals of the chaotic model has been extensively used in topics related toimage processing, while it has not been used much in the context of hiding information. In the method proposed in this article, the histogram of the image is employed for finding the gray surfaces of the pixels of the cover image, each of which pixels covers one bit of the encrypted data. This greatly enhances the capacity for hiding information. On the other hand, the main duty of the chaotic model is the balanced distribution of the bits of

In resource-constrained communication environments, important image data needs to be compressed before encrypted transmission. This paper proposes effective solutions to this issue. Firstly, a new one-dimensional discrete chaotic system model was constructed based on the logistic system and fractional structure. Through theoretical analysis combined with numerical simulation experiments, it has been proven that the proposed new system has excellent chaotic characteristics. Compared with some traditional one-dimensional chaotic systems, the new system has a wider range of chaotic parameters and stronger complexity, making it more suitable for image data encryption. Secondly, a high-compression-ratio image compression method based on improved lifting wavelet transform and a fast image encryption algorithm based on the new chaotic map are proposed. Simulation experiments and security analysis results show that the proposed image compression–encryption scheme has excellent performance and less time overhead. It has good resistance to various cryptanalysis attacks and strong robustness to noise and data loss attacks, which indicates that the proposed image compression–encryption scheme has good application potential in resource-constrained communication environments. The main contribution of this article is the design of a new chaotic system model with practical performance and the development of a new application case. The main novelty of this paper is the proposal of a fast algorithm for high compression ratio and encryption of images.

A novel image encryption algorithm based on SPWLCM and DNA coding