Information security holds paramount importance in the contemporary information society. Here, a novel cryptography method is proposed based on the multi‐wavelength complex‐amplitude metasurface, which can achieve a high security level by generating a frequency‐selective key as an additional layer of protection. Moreover, the quality of the decrypted holographic images can be significantly improved by employing the complex‐amplitude encoding method and the modified visual secret sharing scheme, which adopts a new superposition operator to prevent fidelity loss. As a proof‐of‐concept demonstration, a prototype metasurface sample is designed, fabricated, and characterized, where the measured results agree very well with the numerical ones and the design goals. The proposed method can reinforce security level and improve fidelity of the decrypted message, rendering it appealing for applications in communication and anti‐counterfeiting.

中文翻译：

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多波长超表面加密技术可提高安全性和保真度

信息安全在当代信息社会中至关重要。这里，提出了一种基于多波长复振幅超表面的新型密码学方法，该方法可以通过生成频率选择密钥作为附加保护层来实现高安全级别。此外，通过采用复振幅编码方法和改进的视觉秘密共享方案，可以显着提高解密的全息图像的质量，该方案采用新的叠加算子来防止保真度损失。作为概念验证演示，设计、制造并表征了原型超表面样品，测量结果与数值结果和设计目标非常吻合。所提出的方法可以增强安全级别并提高解密消息的保真度，使其在通信和防伪方面具有吸引力。