With the escalating flow of information and digital communication, information security has become an increasingly important issue. Traditional cryptographic methods are being threatened by advancing progress in computing, while physical encryption methods are favored as a viable and compelling avenue. Metasurfaces, which are known for their extraordinary ability to manipulate optical parameters at the nanoscale, exhibit significant potential for the revolution of optical devices, making them a highly promising candidate for optical encryption applications. Here, a single-sized metasurface with four independent channels is proposed for conducting steganography and multi-key information encryption. More specifically, plaintext is transformed into a ciphertext image, which is encoded into a metasurface, while the decryption key is discretely integrated into another channel within the same metasurface. Two different keys for steganographic image unveiling are also encoded into the metasurface and can be retrieved with different channels and spatial positions. This distributed multi-key encryption approach can enhance security, while strategically distributing images across distinct spatial zones serves as an additional measure to reduce the risk of information leakage. This minimalist designed metasurface, with its advantages of high information density and robust security, holds promise across applications including portable encryption, high-camouflaged image display, and high-density optical storage.

中文翻译：

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一种用于图像隐写术和多密钥信息加密的单尺寸超表面


随着信息流和数字通信的不断升级，信息安全已成为一个日益重要的问题。传统的加密方法正受到计算进步的威胁，而物理加密方法则被视为一种可行且引人注目的途径。超表面以其在纳米尺度上操纵光学参数的非凡能力而闻名，在光学器件的革命中表现出巨大的潜力，使其成为光学加密应用非常有前途的候选者。在这里，提出了一种具有四个独立通道的单一尺寸超表面，用于进行隐写术和多密钥信息加密。更具体地说，明文被转换为密文图像，密文图像被编码为超表面，而解密密钥被离散地集成到同一超表面内的另一个通道中。用于隐写图像揭幕的两个不同键也被编码到超表面中，并且可以使用不同的通道和空间位置进行检索。这种分布式多密钥加密方法可以增强安全性，而战略性地将图像分布在不同的空间区域是降低信息泄露风险的另一种措施。这种极简设计的超表面具有信息密度高和安全性强等优点，有望应用于便携式加密、高伪装图像显示和高密度光存储等应用。