High-security computational optical encryption enabled by single-pixel imaging and reconfigurable meta-holograms

Abstract

The increasing demand for data security in the digital age has exposed the limitations of traditional data-at-rest encryption, including vulnerabilities in key management and insufficient ability to withstand attacks. Here, we propose a hybrid optical cryptography framework that integrates dynamic optical hardware with algorithmic co-design to provide multi-level protection. In the encryption process, the target information is encrypted using the single pixel imaging (SPI) principle, and the ciphertext is generated by mixing the false information with the bucket signal obtained by SPI. The decryption key is generated by the reconfigurable metasurface. This metasurface is based on the phase change material (PCM) Sb₂Se₃, which can be laser-induced to enable key switching for each encryption process, thus realizing "one-time pad" (OTP). In the decryption process, the key obtained from loading at the metasurface can decrypt the information from the ciphertext. The target image is finally decrypted through different channels using Visual Secret Sharing (VSS) scheme. Decryption requires superposition of all shares, thereby enhancing resistance against brute-force and eavesdropping attacks. Furthermore, we analyze the reconfigurability of the metasurface as well as the fabrication tolerance. The results show the strong robustness and high security of our encryption scheme. This approach not only addresses the limitations of fixed-function metasurfaces but also establishes a scalable paradigm for high-security optical encryption in real applications.