An image encryption scheme based on the MLNCML system using DNA sequences

An image encryption scheme based on new spatiotemporal chaos

The coupled map lattices (CML) is a spatiotemporal chaotic system with complex dynamic behavior. In this paper, we propose a spatiotemporal chaotic system with a novel pseudo-random coupling method based on elementary cellular automata (ECA), and introduce different perturbations into lattices in each iteration according to ECA. We investigate the spatiotemporal dynamic properties and chaotic behaviors of the proposed system such as bifurcation diagrams, Kolmogorov Sinai entropy, and uniformity. Moreover, the randomness of sequences generated by the proposed system and the correlation between any two lattices are discussed. Theory analyses and simulations indicate that the new system has better performance in complexity, ergodic and unpredictability than other CML systems such as adjacent CML and nonlinear CML based on fractional order logistic equation, etc. Furthermore, the correlation coefficient between any two lattices in the proposed system is significantly lower than other systems, and another advantage of the proposed system is utilizing the output of ECA to perturb the chaotic system which can effectively alleviate the dynamical degradation in digital system. The excellent performance of the proposed system demonstrates that it has great potential for crypto-system.

Garca Guirao and Lampart (J Math Chem 48:66–71, 2010; J Math Chem 48:159–164, 2010) said that for non-zero couplings constant, the lattice dynamical system is more complicated. Motivated by this, in this paper, we prove that this coupled map lattice system is Li–Yorke chaotic for coupling constant \({0 < \epsilon <1 }\) .

The security of digitally shared data like images, audio and video incurs many security and privacy-related challenges such as unauthorized access. In this work, a video encryption technique using improved sine map and DNA sequencing has been proposed. The proposed video encryption process mainly consists of three phases. In the first phase, key is generated using SHA-256. The second phase comprises of permutation of the video frame using SHA-256 key and improved sine map. In the final phase, diffusion is performed of the permutated frame by using SHA-256 and DNA sequencing, to obtain encrypted video. The experimental outcomes unveil that the obtained entropy of the encrypted video frames is approximately 8 that reflects high randomness in the encrypted frame, and it has low correlation coefficients among neighbouring pixels in all three horizontal, vertical and diagonal directions. The presented scheme of video encryption is resistant to threats like brute force attack, plaintext attack and statistical attack.

This paper presents a novel encryption scheme based on genetic operations and Mixed Linear-Nonlinear Coupled Logistic Map Lattice (MLNCML) spatiotemporal chaotic system. The initial values of the MLNCML system are related to the plain-image. Therefore, this scheme is sensitive to the plaintext and keys. For the simplicity and efficiency of the encryption process, expanded XOR (eXOR) operation and genetic operations are applied in the scheme. Spatiotemporal chaotic system can resist dynamical degradation and periodic phenomena, which offers good randomness for encryption. Moreover, the eXOR operation in this paper can effectively avoid the chosen-plaintext attack of traditional XOR operation. The DNA mutation and crossover operations are controlled by chaotic sequences, which overcome man-in-the-middle attack in the traditional DNA addition and subtraction operation. The experimental results indicate that the proposed scheme has good security to resist common attacks.

A coupled map lattice system is perturbed by a local injection. The system response to the external excitation is investigated. We find a phase transition from local response to a global response. As global response functions the motions of the sites far from the forced site show critical on-off intermittency. The implication of the global response to the physical transportation behavior is addressed.

This paper proposes a novel spatiotemporal chaotic system with two-dimensional dynamic pseudo-random coupled map lattices (2D-DPRCML) based on partitioned elementary cellular automata (PECA). In the system iteration, coupling lattices are chosen based on the chaotic PECA, and the iterative results of PECA are also employed as the perturbation for the system. We investigate the system’s chaotic properties, including bifurcation diagrams, Kolmogorov-Sinai entropy density and universality. In addition, the output sequences were analyzed for uniformity and randomness. The correlations between the system lattices are also explored. The simulation results and theoretical analysis demonstrate that the 2D-DPRCML system possesses excellent chaotic performance, and the output sequences show good uniformity and randomness, indicating that the 2D-DPRCML system is capable of resisting the return maps attack. It is evident from all these advantages that the proposed system is ideal for use in cryptography.

A novel method for one-way hash function construction based on spatiotemporal chaos

In this paper, a new one-way Hash function is proposed based on chaotic neural network. With the neural network with piecewise linear chaotic map as the output function, the key generation function based on spatiotemporal chaotic system are used to realized the data confusion and diffusion. By the cipher block chaining mode, the proposed method can produce 128-bit Hash value for plaintext with arbitrary length. Theoretical analysis and experimental results indicate that the proposed Hash function satisfies the demands in performance, such as being one-way, having initial value and key sensitivity, collision resistance and real-time applicability.

The suppression of the pattern complexity of spatiotemporal chaos in Coupled Acousto-optic Bistable Map Lattice system (CABMLs) is investigated. The pattern complexity of spatiotemporal dynamics is exhibited quantitatively by employing the average Kolmogorov–Sinai (KS) entropy density according to the Lyapunov exponents of lattices. By designing a global control method with periodic state feedback, we provide the stability analysis for suppressing spatiotemporal chaos to a stable state. Then, a pattern control strategy using discrete-space state feedback with equal intervals is proposed. Numerical simulations demonstrate that the pattern complexity of spatiotemporal chaos is decreased to a low level by the proposed method. Finally, the dependence of the control effect on the control interval is discussed in detail by considering the control efficiency and control cost and the optimal control interval is obtained.

A universal selective image encryption algorithm, in which the spatiotemporal chaotic system is utilized, is proposed to encrypt gray-level images. In order to resolve the tradeoff between security and performance, the effectiveness of selective encryption is discussed based on simulation results. The scheme is then extended to encrypt RGB color images. Security analyses for both scenarios show that the proposed schemes achieve high security and efficiency.

Based on symbolic dynamics, a novel computationally efficient algorithm is proposed to estimate the unknown initial vectors of globally coupled map lattices (CMLs). It is proved that not all inverse chaotic mapping functions are satisfied for contraction mapping. It is found that the values in phase space do not always converge on their initial values with respect to sufficient backward iteration of the symbolic vectors in terms of global convergence or divergence (CD). Both CD property and the coupling strength are directly related to the mapping function of the existing CML. Furthermore, the CD properties of Logistic, Bernoulli, and Tent chaotic mapping functions are investigated and compared. Various simulation results and the performances of the initial vector estimation with different signal-to-noise ratios (SNRs) are also provided to confirm the proposed algorithm. Finally, based on the spatiotemporal chaotic characteristics of the CML, the conditions of estimating the initial vectors using symbolic dynamics are discussed. The presented method provides both theoretical and experimental results for better understanding and characterizing the behaviours of spatiotemporal chaotic systems.

Intelligent home products have serious information security risks, threatening the privacy of users. In this paper, a method of password protection using hyper-chaos based one-way hash function and secure information transmission method based on spatiotemporal chaos are proposed. The proposed method creates a unidirectional hash function using the delay induced hyper-chaotic system and the key stream iteration to protect user password and to realize user authentication. At the same time, the chaotic time series generated by the one way coupled map lattice system is used to encrypt the plaintext information for the data secure communication, which increases the security of the intelligent home system. An intelligent home system prototype is built based on a Zigbee network, cloud server, and Android system.

Many complex and interesting spatiotemporal patterns have been observed in a wide range of scientific areas. In this paper, two kinds of spatiotemporal patterns including spot replication and Turing systems are investigated and new identification methods are proposed to obtain Coupled Map Lattice (CML) models for this class of systems. Initially, a new correlation analysis method is introduced to determine an appropriate temporal and spatial data sampling procedure for the identification of spatiotemporal systems. A new combined Orthogonal Forward Regression and Bayesian Learning algorithm with Laplace priors is introduced to identify sparse and robust CML models for complex spatiotemporal patterns. The final identified CML models are validated using correlation-based model validation tests for spatiotemporal systems. Numerical results illustrate the identification procedure and demonstrate the validity of the identified models.

Adaptive control of spatiotemporal chaos in coupled map lattices