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Security and Communication Networks
Volume 2018, Article ID 2708532, 13 pages
https://doi.org/10.1155/2018/2708532
Research Article

A New Chaos-Based Color Image Encryption Scheme with an Efficient Substitution Keystream Generation Strategy

School of Computer Science and Engineering, Northeastern University, Shenyang 110004, China

Correspondence should be addressed to Chong Fu; nc.ude.uen.liam@gnohcuf

Received 10 August 2017; Accepted 3 January 2018; Published 20 February 2018

Academic Editor: Leo Y. Zhang

Copyright © 2018 Chong Fu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper suggests a new chaos-based color image cipher with an efficient substitution keystream generation strategy. The hyperchaotic Lü system and logistic map are employed to generate the permutation and substitution keystream sequences for image data scrambling and mixing. In the permutation stage, the positions of colored subpixels in the input image are scrambled using a pixel-swapping mechanism, which avoids two main problems encountered when using the discretized version of area-preserving chaotic maps. In the substitution stage, we introduce an efficient keystream generation method that can extract three keystream elements from the current state of the iterative logistic map. Compared with conventional method, the total number of iterations is reduced by 3 times. To ensure the robustness of the proposed scheme against chosen-plaintext attack, the current state of the logistic map is perturbed during each iteration and the disturbance value is determined by plain-pixel values. The mechanism of associating the keystream sequence with plain-image also helps accelerate the diffusion process and increase the degree of randomness of the keystream sequence. Experimental results demonstrate that the proposed scheme has a satisfactory level of security and outperforms the conventional schemes in terms of computational efficiency.