Color Image Encryption Based On Chaotic System

The 21 st century is the era of global information. Information is related to personal privacy or commercial confidentiality, or even the national security. The past few years have witnessed a mounting number of information thefts and hostile attacks, so the security of information becomes more and more important. Digital color image is an important information carrier, but traditional encryption methods are not so suitable for digital image encryption. The chaotic system has properties of sensitivity to initial conditions, unpredictability, pseudo-randomness and so on. All these special characteristics make chaos suitable for image encryption. This paper make a study on chaos based color image encryption.A color image encryption by combining Chua's circuit and Chen's hyper-chaotic system is proposed. The algorithm regards image components R, G, B as the units and encrypts each unit independently. The pixel values of the RGB components from color image are substituted by Chua's chaotic circuit. Chen's hyper-chaotic system is utilized to permute the positions of image pixels. Security analyses demonstrate that the algorithm has good encryption performance and high security.Then, a new color image encryption algorithm based on Logistic map and hyperchaotic Lorenz system is proposed for the high correlations between R, G, B components. Specifically, Logistic map is utilized to insert rows of G, B into R to shuffle the pixel positions in the confusion phase, which reduce the high correlations between R, G, B components effectively. Hyperchaotic Lorenz system is employed to diffuse the shuffled image. Security analyses show that the proposed algorithm can achieve good encryption effect and is robust against common attacks.