A novel color image encryption scheme using elliptic curve cryptography and hyperchaotic system

Abstract

This paper develops an asymmetric color image encryption algorithm based on elliptic curve cryptography(ECC), five dimensions(5D) hyperchaotic system, and DNA dynamic coding. To embed the characteristics of original image in the image encryption algorithm, this algorithm builds a mathematical model to strengthen the connection between the original image, elliptic curve Diffie-Hellman(ECDH) algorithm and hyperchaotic system. The red, green and blue(RGB) channels of encrypted image is reshaped into a three dimensions(3D) matrix. Grouping and scrambling of 3D matrix is accomplished at pixel level, bit level and DNA level based on a 5D hyperchaotic system, which effectively enhances the cross-layer variation of images. Then, improved ECC is performed on the scrambled image where multiple elliptic curves and dynamic shared private keys can guarantee the forward secrecy of the image encryption algorithm. At last, the image is performed diffusion to obtain the final encrypted image. Simulation results and security analysis both indicate the image encryption algorithm has better performances in terms of key space, Shannon entropy, clipping attack resistance, etc.