A Fast Hyperchaotic Image Encryption Scheme

In this paper, we propose a fast hyperchaotic image encryption scheme based on RSVM and step-by-step scrambling-diffusion. In this scheme, we firstly propose a new algorithm named ring shrinkage with variable modulo (RSVM), which can randomly scramble the elements in a one-dimensional array, which are composed of the row numbers or column numbers of the pixel matrix to be encrypted. Before encryption, we use RSVM algorithm to generate two random one-dimensional arrays of pixel matrix (i.e. row array A(s )and column array B-s), and each element in the A(s)/B-s represents the row/column number in the pixel matrix. Then the rows/columns of the pixel matrix are scrambled-diffused step-by-step according to the row/column numbers in the A(s)/B-s. The initial control parameters of RSVM algorithm are controlled by SHA-256 of plaintext pixels, and RSVM algorithm controls the step-by-step scrambling-diffusion process of pixel matrix, rows and columns, so the small changes of plaintext pixels will lead to great differences in ciphertext images. In addition, the overall time complexity of the image encryption scheme is only T(1.5(M + N)), which can greatly reduce the time cost. Finally, the experimental results and extensive security analysis prove the efficiency and feasibility of this image encryption method.

Automated summary

In this paper, a fast hyperchaotic image encryption scheme based on RSVM and step-by-step scrambling-diffusion is proposed. The scheme utilizes the RSVM algorithm to generate random one-dimensional arrays of the pixel matrix, which are then used to scramble-diffuse the rows/columns of the pixel matrix. The control parameters of the RSVM algorithm are determined by the SHA-256 of the plaintext pixels, ensuring that even small changes in the plaintext pixels result in significant differences in the ciphertext images. Additionally, the overall time complexity of the scheme is quite low, reducing the time cost significantly.