Image Encryption Algorithm Based on Quantum Chaotic Mapping and Wavelet Transform

Aiming at the problems of low security and slow encryption speed of traditional chaotic system, this paper designs a wavelet domain image encryption algorithm which combines quantum chaotic mapping and Lorenz hyper chaotic mapping. Firstly, the SHA-256 hash algorithm is used to generate the initial key, and the quantum chaotic sequence and Lorenz hyper chaotic sequence are generated iteratively. Then, the plaintext image matrix is decomposed by discrete wavelet, and the sub-band coefficient matrix of each component after decomposition is scrambled by quantum chaotic sequence, and then it is reconstructed by discrete wavelet to complete the scrambling. Finally, Lorenz hyper chaotic sequence is used to diffuse the scrambled images, and the cipher text images after secondary encryption are obtained and analyzed for security. The simulation results show that the chaotic sequence combined with quantum chaos and used for encryption can be associated with the plaintext image through SHA-256, and the way of wavelet domain scrambling can get a better encryption effect, good performance against all kinds of attacks, and has the characteristics of high security and fast computing speed.