Wei, ZhuangkunLi, BinGuo, Weisi2023-05-022023-05-022023-04-12Wei Z, Li B, Guo W. (2023) Adversarial reconfigurable intelligent surface against physical layer key generation. IEEE Transactions on Information Forensics and Security, Volume 18, 2023, pp. 2368-23811556-6013https://doi.org/10.1109/TIFS.2023.3266705https://dspace.lib.cranfield.ac.uk/handle/1826/19564The development of reconfigurable intelligent surfaces (RIS) has recently advanced the research of physical layer security (PLS). Beneficial impacts of RIS include but are not limited to offering a new degree-of-freedom (DoF) for key-less PLS optimization, and increasing channel randomness for physical layer secret key generation (PL-SKG). However, there is a lack of research studying how adversarial RIS can be used to attack and obtain legitimate secret keys generated by PL-SKG. In this work, we show an Eve-controlled adversarial RIS (Eve-RIS), by inserting into the legitimate channel a random and reciprocal channel, can partially reconstruct the secret keys from the legitimate PL-SKG process. To operationalize this concept, we design Eve-RIS schemes against two PL-SKG techniques used: (i) the CSI-based PL-SKG, and (ii) the two-way cross multiplication based PL-SKG. The channel probing at Eve-RIS is realized by compressed sensing designs with a small number of radio-frequency (RF) chains. Then, the optimal RIS phase is obtained by maximizing the Eve-RIS inserted deceiving channel. Our analysis and results show that even with a passive RIS, our proposed Eve-RIS can achieve a high key match rate with legitimate users, and is resistant to most of the current defensive approaches. This means the novel Eve-RIS provides a new eavesdropping threat on PL-SKG, which can spur new research areas to counter adversarial RIS attacks.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/EavesdroppingReconfigurable intelligent surfacePhysical layer secret keyWireless CommunicationArticle