Metasurface-enhanced optical encryption via authentication and steganography co-design

Abstract

Metasurface-empowered optical encryption has emerged as a transformative paradigm in high-security optical systems. This study introduces a metasurface-based holographic encryption that integrates steganography and authentication strategies. During the encryption process, the secret image and the authentication image are separately encoded into two phase-only holograms (POHs) with steganographic capabilities. These POHs are then encoded onto different polarization channels of the metasurface. For decryption, the receiver must retrieve the speckle pattern for authentication via joint utilization of the metasurface and a pre-shared authentication key. Only upon successful authentication can the decryption key be applied to reconstruct the concealed image. This holographic encryption via authentication and steganography co-design not only expands the metasurface’s information capacity but also establishes a hierarchical security barrier against unauthorized decryption attempts. Numerical simulations validate the feasibility and security of the proposed method.