Compressive Imaging Encryption with Secret Sharing Metasurfaces

Exploiting various degrees of freedom of light, metasurfaces have unique advantages in multiple‐channel information storage and demonstration, which thereby provides a novel platform to convey the keys and cipher images for different encryptions. Following the secret sharing principle of visual cryptography (VC), the authors here successfully embed both the keys and cipher images of computational ghost imaging (CGI) encryption into the holographic metasurface‐images (meta‐images). The decryption process starts with key retrieval via optical observation of overlapped meta‐images, followed by a compressive CGI calculation to reconstruct the target images according to the obtained key and steganographic cipher images with a high compression ratio of 4. By integrating metasurface imaging, VC, and CGI, the authors’ proposed encryption scheme exempts conventional key distribution and transmission of CGI, enhances the security by secret sharing of VC, and increases the amount of hiding data contained in meta‐images with compressive sensing. Metasurface holography, visual cryptography (VC), and computational ghost imaging (CGI) are integrated to propose an encryption scheme, where both keys and ciphertext of CGI are hidden into the secret sharing metasurfaces in a high compression ratio of 4. Two images can be decoded by obtaining keys (i.e., superimposing two meta‐images directly), and cipherimages (i.e., read from piece of meta‐images).