Multidimensional Information‐Encoding Metasurface for Key‐Concealed Physical‐Layer Secure Communications

Metasurface‐based secure communication has been extensively investigated, offering a new avenue for direct wireless physical‐layer encryption. However, most existing schemes are still restricted to single‐dimensional electromagnetic encryption and rely on key pre‐distribution, which limits both the communication security and information‐carrying capacity of the system. Here, we propose a key‐concealed encryption method based on a multidimensional information‐encoding metasurface (MIEM), which jointly incorporates amplitude, phase, and polarization coding into physical‐layer secure communication. This method hybrid‐encrypts the original information with random keys and further distributes them across mutually independent electromagnetic dimensions, thereby enabling the integrated collaborative transmission of the key and payload at the physical layer. As an experimental demonstration, we design and fabricate a MIEM that enables independent control of the amplitude, phase, and polarization of electromagnetic waves, and validate the proposed method through image‐encrypted key‐concealed transmission experiments. This work constructs a key‐concealed secure communication architecture based on extending the electromagnetic manipulation dimensions of a reconfigurable metasurface, providing a new paradigm for high‐security and large‐capacity physical‐layer secure communication.