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Liu H.,Dalian University of Technology | Liu H.,Weifang Vocational College | Wang X.,Dalian University of Technology
Optics Communications | Year: 2011

This paper proposes a bit-level permutation and high-dimension chaotic map to encrypt color image. Firstly, convert the plain color image of size (M × N) into a grayscale image of size (M × 3N), then transform it into a binary matrix, and permute the matrix at bit-level by the scrambling mapping generated by piecewise linear chaotic map (PWLCM). Secondly, use Chen system to confuse and diffuse the red, green and blue components simultaneously. Experiment results and security analysis not only show that the scheme can achieve good encryption result, but also that the key space is large enough to resist against common attack. © 2011 Elsevier B.V. All rights reserved. Source


Liu H.,Dalian University of Technology | Liu H.,Weifang Vocational College | Wang X.,Dalian University of Technology | Kadir A.,Xinjiang University of Finance and Economics
Applied Soft Computing Journal | Year: 2012

This paper proposes a novel confusion and diffusion method for image encryption. One innovation is to confuse the pixels by transforming the nucleotide into its base pair for random times, the other is to generate the new keys according to the plain image and the common keys, which can make the initial conditions of the chaotic maps change automatically in every encryption process. For any size of the original grayscale image, after being permuted the rows and columns respectively by the arrays generated by piecewise linear chaotic map (PWLCM), each pixel of the original image is encoded into four nucleotides by the deoxyribonucleic acid (DNA) coding, then each nucleotide is transformed into its base pair for random time(s) using the complementary rule, the times is generated by Chebyshev maps. Experiment results and security analysis show that the scheme can not only achieve good encryption result, but also the key space is large enough to resist against common attacks. © 2012 Elsevier B.V. All rights reserved. Source


Liu H.,Dalian University of Technology | Liu H.,Weifang Vocational College | Wang X.,Dalian University of Technology | Kadir A.,Xinjiang University of Finance and Economics
Optik | Year: 2013

This paper proposes a color image encryption scheme based on Choquet fuzzy integral (CFI) and hyper chaotic system. The major core of the encryption algorithm is a pseudo-random number generator based on the CFI. Before encrypting the color image, the piecewise linear chaotic map (PWLCM) is used to generate the 128-bit secret keys, and the Lorenz system is iterated for limited times to generate the initial parameters of the CFI. The outputs of the CFI are used to confuse and diffuse the three components of the pixel, respectively. Experiment results and security analysis show that the scheme not only can achieve good encryption result and large key space, but also can resist against common attacks, so the scheme is reliable to be adopted for network security and secure communications. © 2012 Elsevier GmbH. Source


Liu G.,Weifang Medical University | Li J.,Weifang Medical University | Liu H.,Weifang Vocational College
Computers in Biology and Medicine | Year: 2014

This paper proposes an improved chaos-based color pathological image encryption algorithm, using SHA-2 to generate one-time keys. In order to send different ciphered images to different recipients, the hash value of the plain image and a random number are applied to generate one-time initial conditions for Chebyshev maps, to make the key stream change in every confusion process without changing the common initial values. The permuted image is divided into 256-bit long blocks, the avalanche effect is applied to diffuse the blocks, i.e., each block is XORed with the hash value of the prior block. Simulation results demonstrate that the proposed algorithm is robust against common attacks. © 2013 Elsevier Ltd. Source


Liu H.,Dalian University of Technology | Liu H.,Weifang Vocational College | Wang X.,Dalian University of Technology | Zhu Q.,Dalian University of Technology
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2011

This Letter designs an asynchronous hyper chaotic secure communication system, which possesses high stability against noise, using dynamic delay and state variables switching to ensure the high security. The relationship between the bit error ratio (BER) and the signal-to-noise ratio (SNR) is analyzed by simulation tests, the results show that the BER can be ensured to reach zero by proportionally adjusting the amplitudes of the state variables and the noise figure. The modules of the transmitter and receiver are implemented, and numerical simulations demonstrate the effectiveness of the system. © 2011 Elsevier B.V. Source

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