Bidirectional Multi‐Channel Programmable Metasurface for High‐Security Wireless Information Steganography

ABSTRACT

With inherent abilities of directly modulating digital information on reflection and transmission properties, programmable metasurfaces have been extensively explored in wireless communications. However, realizing multi‐channel metasurface‐based wireless communication that fully exploits spatial resources while ensuring high information security still remains a challenge. Here, a multi‐channel information steganography strategy is proposed by integrating a bidirectional full‐space programmable metasurface with software‐layer encryption algorithms to enhance both security and capacity of omni‐wireless communication. Embedded with tunable components, the reconfigurable metasurface is engineered with independent dynamic 1‐bit phase modulation capabilities in three diversely polarized reflection and transmission wireless channels. By concealing target messages into camouflage images using steganography techniques, malicious eavesdropping from unauthorized users is prevented even with access to the transmitted data. Experiments are conducted to verify that the proposed approach is able to realize multi‐channel wireless communication and information steganography. Illegitimate users are constrained to the confidential carrier images, and the target messages can only be retrieved by authorized accesses based on the pre‐agreed encryption scheme. This work may offer untapped potentials for future multi‐channel full‐space secure wireless communications.