A novel design of multiple image encryption using perturbed chaotic map

For recent decades, the increasing volume of multimedia data has been witnessed, and the data is required technical methods to assure the security for storage and transmission. Chaos-based encryption is one of promising approaches to keep large volume of data confidential. Most of chaos-based algorithms were proposed for single image encryption. Recently, several schemes were proposed for multiple image encryption, and all of them are designed to work in a single round of encryption. In addition, the dynamics of chaotic maps therein are stationary, so it does not provide advantage of uncertainty of chaotic orbits for the security. Moreover, a chaotic map being realized in digital platforms can produce a large number of bits, and so far those bits have not been used efficiently to encrypt larger volume of data. In this paper, a novel design of chaos-based multiple image encryption is proposed using the permutation-diffusion architecture for the first time. Any chaotic map can be employed for the proposed design. Chaotic dynamics are non-stationary by means of perturbation on state variables and control parameters in bit level. Amounts of perturbation are constructed from the coordinate of pixels and the content of plain images respectively in the pixel permutation and diffusion processes, so the proposed design provides the property of authentication. Values of chaotic state variables are represented in fixed-point number, and bits generated by chaotic maps are thoroughly exploited to encrypt multiple images at the same time. The specific example will demonstrate the effectiveness of the proposed design by means of the statistical and security analyses. The simulation results will show its resistance from the attacking method of differential analysis, and those are also compared with those of other existing algorithms.