Encryption Algorithms Of Quantum Image Based On Phase Shift Transformation

With the innovation of science and technology,image encryption plays a very important role in the secure exchange and storage of important resources such as information and scientific research achievements.Quantum image encryption algorithm associates the quantum image with the traditional image processing,and then stores the original image and the encrypted quantum image in quantum states.Quantum image encryption is more efficient and safer than classic image encryption by using unique properties of quantum computing,such as hyper parallel computing and quantum non-cloning principle.The quantum image representation model NASS?Normal Arbitrary Superposition State?can represent both gray image and color image,and only needs n quantum bits to store a quantum image of 2ⁿ pixels.Therefore,this dissertation proposed two quantum encryption algorithms,encryption objects of which are NASS quantum images.The main research work is summarized as follows:1.A quantum encryption algorithm based on phase shift transform and quantum Fourier transform is proposed,and the corresponding quantum implementation circuit is designed.The simulation results show that the algorithm has good anti-attack performance.Simulation experiments show that there are?2ⁿ+4?random keys in the algorithm,and the key space is large,which improves the encryption efficiency,and the pixel change rate is large.The adjacent pixels of the encrypted image are weakly correlated and the histogram is flat.The algorithm has good anti-attack performance.Compared with Optical image encryption based on input plane and Fourier plane random encoding,the key space is large and the complexity is low.The key space is larger compared to Novel image encryption/decryption based on quantum Fourier transform and double phase encoding.2.NASS quantum image is encrypted by combining geometric transform,random phase shift transform?RPST?and quantum Haar wavelet packet transform?QHWPT?.Firstly,the scrambled image is obtained by geometric transformation.Next,the phase-shifting operation is improved.Meanwhile,the corresponding quantum implementation circuit is designed.Then,the image are performed by using RPST and QHWPT.Finally,RPST and QHWPT are performed again.There are2^?n+1?-2 randomly selected keys in the scheme.Random phase shift transformation increases the flexibility of the key.The experiment results show that keys and results of each simulation are different,and the pixel change rate is large,which can resist external cracking.Compared with quantum image encryption algorithm based on NASS,the adjacent pixels of the encrypted image are more evenly distributed,and the key space and pixel change rate are larger.