A symmetric color image encryption algorithm using the intrinsic features of bit distributions

In recent years, a variety of chaos-based image encryption algorithms have been proposed. Most of them employ the confusion-diffusion architecture and operate at the pixel level. In this paper, we analyze the intrinsic features of the bit distributions, the high correlation among bit planes and other issues related to the bit information of an image. Due to the superior characteristics of bit-level operations and the intrinsic bit features of the image, an expand-and-shrink strategy is employed to shuffle the image with reconstructed permuting plane. Simulations have been carried out and the results demonstrate the superior security and high efficiency of the proposed scheme.

► We find that the bit values of higher neighbor bit planes in natural images always have opposite values.
► We find that the bit distribution of a natural image is stable in macroscopic but oscillatory in microscopic.
► Based on the two features, an “expand-and-shrink” strategy is used in the proposed color image cryptosystem.
► Compared with cryptosystem BLP, the simulation results show that our scheme is better.