A chaos-based image encryption algorithm using wavelet transform

In recent years many chaos-based image cryptosystems are proposed. As encryption process is applied to the whole image, it is difficult to improve the efficiency. In this paper, wavelet decomposition is used in our algorithm to concentrate the main information of image to the low frequency part. Then high-strength chaotic encryption is applied. After that, wavelet reconstruction and Arnold scrambling are used for diffusion. Finally, another wavelet decomposition and encryption round is needed to complete the encryption. The effective acceleration of chaos-based image cryptosystem is thus achieved. Theoretical analysis and experimental results show that the proposed algorithm has large key-space, high efficiency, and satisfied security, suits for image data transmission.