A Spatiotemporal Chaotic System Based on Pseudo-Random Coupled Map Lattices and Elementary Cellular Automata

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 the elementary cellular automata (ECA), and add different perturbations to 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 density, and universality. Moreover, the correlation between any two lattices is discussed. Theory analysis and simulation test indicate that the new system has better performance in complexity, ergodic and unpredictability than conventional CML systems such as adjacent CML and mixed linear-nonlinear CML. Furthermore, the correlation coefficient between any two lattices in 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 proposed system demonstrates that it has great potential for crypto-system.

A Novel Method for Constructing the S-Box Based on Spatiotemporal Chaotic Dynamics

A novel construction method for a random S-box by using the spatiotemporal nonlinear chaotic system is proposed. The chaotic sequences of the spatiotemporal chaotic system are applied to construct an initial S-box. Then, the permutation operation between independent chaotic sequences is performed to shuffle the elements of the S-box randomly. In comparisons with the former schemes, the results of the performance analysis indicate that the obtained S-box has a better output bit independence criterion and a stronger ability to resist linear password attacks. It also has a high dimensional feature due to the spatiotemporal chaotic dynamical behaviors. The proposed scheme holds superior cryptographic features.

A Wheel-Switch Selective Image Encryption Scheme Using Spatiotemporal Chaotic System

In this paper, we propose a novel selective image encryption scheme using a one-way coupled map lattice (CML) consisting of logistic maps and a selector constructed by two variants of a cyclic shift register (VCSR). The initial conditions and the coupling constant of CML in our scheme are influenced by all the contents of the plain image. Moreover, the selector is closely related to the nonencrypted part of the plain image. In addition, we select only a portion of image data to encrypt via a wheel-switch scheme governed by the selector. Users can select an appropriate proportion to encrypt the plain image for their different demands of security and efficiency. Experimental results and theoretical analysis show that the cryptosystem is effective and can resist various typical attacks.

A Robust Secondary Secure Communication Scheme Based on Synchronization of Spatiotemporal Chaotic Systems

This paper deals with the synchronization of spatiotemporal chaotic systems and presents a new robust secondary chaotic secure communication system for digital signal transmissions which can recover digital signal even though the transmitted signal is influenced by limited noise. The transmitter terminal and the receiver terminal both contain a spatiotemporal chaotic system and a hyperchaotic system. The asymptotic convergence of the errors between the states of the transmitter terminal and the receiver terminal has been proved based on the Lyapunov stable theory and active-passive decomposition (APD) method. Moreover, a random digital signal and a binary Lena image are encrypted and decrypted successfully to verify the efficiency of the proposed robust secure communication system.