Image encryption scheme based on pseudo-DWT and cubic S-box

Abstract

Combining a pseudo-Discrete Wavelet Transform (pseudo-DWT) and a novel cubic S-box technique, an image encryption scheme using a newly-developed four-dimensional hyperchaotic system (NewHS) is presented in this paper. The principal advantage of this method resides in its enhanced security, with hash values (computed by SHA-256) of the plaintext, thereby bolstering resistance to chosen-plaintext attack. Initially, a novel three-dimensional cubic S-box is designed via chaotic sequence, increasing the complexity and randomness. Subsequently, the proposed scheme employs a Ladder permutation for image scrambling, achieving a one-time pad encryption effect. Finally, a pseudo-DWT is devised to segment and reconstruct the image, implementing scrambling and diffusion encryption. Moreover, experiments and security analysis also prove that the proposed encryption scheme can show good performance.