Quantum meaningful visual cryptography

The quantum visual encryption scheme utilizes quantum property to encrypt secret information, which increases the security of secret information. However, its share images are meaningless noisy images. Therefore, the share image is vulnerable to be attacked after quantum measurement. To further improve the security of image data transmission, we propose a (n, n) quantum meaningful visual encryption scheme. The scheme consists of two phases, the encryption phase and the recovery phase. The secret image is a binary image and n cover images are halftone images. In the encryption phase, either the secret image pixel or the cover image pixel is randomly selected for encryption by a quantum selection circuit. The color information of each pixel of the secret image and the cover image is then encoded as n-qubit superposition state. Finally, these qubits are divided among the n participants. In the recovery stage, n participants work together to collect all the qubits of each pixel and perform n-qubit OR operation to recover the secret information. Simulations were carried out to verify the feasibility of this scheme. The share images in this scheme are meaningful and retain the advantage of single-pixel parallel processing.