Research On Optical Image Encryption Algorithem Based On QR Code

As an important way of information transmission,image security is becoming increasingly important.Based on the optical encryption technologies,several image encryption algorithms have been proposed in this thesis by introducing QR code,and the details are described as follows:1.An image encryption algorithm has been proposed based on QR code and high-dimensional chaotic system.The image to be encrypted is converted into QR code,and then encoded into the ciphertext with noise-like distribution by using cascaded gyrator transforms.The iterative phase retrieval process is used to decrypt the original QR code.After the iteration process stops,the original image without any information loss can be reconstructed by scanning the decrypted QR code with a mobile device.The ciphertext image is a real-valued function,which is more convenient to store and transmit.Meanwhile,due to the high sensitivity of Chen system's initial value,the security of the scheme is greatly improved.The feasibility and effectiveness of the scheme are verified through a large number of cryptographic analyses and simulations.2.A multi-image encryption scheme has been proposed based on vector quantization and interference.The images to be encrypted are firstly converted into QR codes,and compressed by using the codebook,which is generated with other QR code.These compressed QR codes are integrated with the help of space multiplexing technique,and then scrambled.Finally,the scrambled interim is encrypted into the ciphertext image.The decryption process is an inverse process of the encryption process.Through a series of numerical experiments and security analysis,it can be concluded that the proposed algorithm has high robustness against occlusion and noise attacks,and its feasibility and effectiveness have been verified.3.An optical image encryption algorithm based on QR code constraints has been proposed.Initially,a data container based on QR code constraint condition is designed to carry the information to be encrypted,and then it is encrypted by using double random phase coding.In the decryption process,the original image can be reconstructed with high quality by using the iterative phase retrieval process,where the additional constraints is helpful.Through a series of simulations,the feasibility and effectiveness of the proposed algorithm have been demonstrated.