Chaotic Image Encryption Algorithm Based on Fractional Order Scrambling Wavelet Transform and 3D Cyclic Displacement Operation

In order to deal with the security of image information, this paper proposes a chaotic image encryption method based on fractional wavelet transform. First, fractional wavelet transform is applied to preprocess the image as a signal. After three-level fractional wavelet decomposition, high-frequency components are obtained with low frequency components. Second, the hash function is used to generate the initial value of the chaotic system for the plaintext operation, and the initial value is brought into the Lorenz system to obtain the chaotic sequence, the chaotic sequence is scrambled for the high frequency components, and the 3D cyclic displacement scrambling is performed for the low frequency components. The high-frequency components and low-frequency components are reconstructed by fractional wavelet transform and restored to the final scrambled image. Last, in order to further deepen the encryption effect, cyclic displacement diffusion is performed on the scrambled image to obtain the final encrypted image. Experimental and simulation results show that the algorithm proposed in this paper has excellent encryption effect and can resist common attack methods.