A novel image encryption scheme based on pseudo-random coupled map lattices with hybrid elementary cellular automata

Abstract

In this paper, a hybrid elementary cellular automata (HECA) composed of two chaotic global rules is designed to enhance the chaotic properties of the pseudo-random coupled map lattices (PRCML) model based on the Chirikov standard map (CSM). Theory analyses and simulations indicate that the PRCML-HECA model exhibits superior chaos. Subsequently, a novel image encryption scheme based on this model is implemented. The scheme consists of key seed generation, encryption, and decryption. A series-wound PRCML-HECA model is designed to generate the key seed related to the plain-image, initial key, and timestamp. This process is nonlinear and irreversible, ensuring the proposed scheme can resist the chosen-plaintext/ciphertext attacks. Furthermore, a dynamic substitution box changed with the key seed is also included in the proposed scheme. Moreover, plenty of statistical and security analyses, such as diffusion, histogram, correlation analyses, etc., are introduced in this paper. The results prove that the proposed image encryption scheme based on the PRCML-HECA model can resist differential and statistical attacks. And the scheme also possesses strong robustness and high efficiency.