Quantum grayscale image encryption and secret sharing schemes based on Rubik’s Cube

In order to encrypt and safely share images using quantum computer, a quantum grayscale image encryption scheme and a quantum grayscale image secret sharing scheme are proposed in this paper. According to Rubik's Cube rotation method, this paper initially puts forward the quantum Rubik's Cube rotation scrambling scheme (QRRSS) to permute the pixel position. Then, based on QRRSS, quantum XOR operation and quantum SWAP operation, we design the quantum image encryption scheme. Finally, we propose a quantum image secret sharing scheme. In the secret sharing scheme, one secret image and six cover images are encrypted. Quantum least significant bit (LSB) method is used to stego the secret image into four randomly chosen cover images in order to generate four shadow images. The shared secret image can be recovered if all the shadow images can be collected from all participants. We then design the whole quantum circuits of two proposed schemes and finish simulation experiments. The simulation results indicate that our encryption scheme and secret sharing scheme have good effect. It is worth noting that the computational complexity of our two proposed quantum algorithms is exponentially decreased than the classical counterparts.