Quantum Image Encryption Algorithms Based On Hyper-Chaotic System And Cross-Exchange Operation

Quantum image processing is a new research field for capturing,processing,and restoring quantum images of different formats and different purposes with quantum computing technology.The parallelism of quantum computing,the superposition and entanglement properties of quantum states make quantum image processing superior to the classic image processing in processing speed and security.In this dissertation,based on the high-dimensional hyper-chaos system,quantum computation and quantum discrete cosine transform,a quantum color image encryption scheme and a quantum image encryption-compression scheme are designed.Simulations and performance analyses are performed on the two image encryption algorithms.The main results of this dissertation are as follows:In order to obtain higher encryption efficiency,a bit-level quantum color image encryption scheme by combining quantum cross-exchange operation with 5D hyper-chaotic system is proposed.To enhance the scrambling effect,the quantum channel swapping operation is employed to swap the gray-values of the corresponding pixels.The proposed color image encryption algorithm has larger key space and higher security since the 5D hyper-chaotic system has more complex dynamic behavior,better randomness and unpredictability than those based on low-dimensional hyper-chaotic systems.Simulations results and security analyses demonstrate that the presented quantum color image encryption scheme is superior to the corresponding classical image encryption scheme in efficiency and security.In order to obtain higher encryption efficiency and certain compression performance of quantum image,a quantum gray image encryption-compression scheme based on quantum discrete cosine transform and 5-dimensional hyper chaotic systems is designed.The image is compressed by the quantum discrete cosine transform,and then the compressed image is encrypted by the 5-dimensional hyper-chaotic system.It is shown that the proposed quantum image encryption-compression scheme performs better than the corresponding classical image encryption-compression scheme in term of efficiency and security.