🤖 AI Summary
This paper demonstrates that noise-based dynamic watermarking fails to provide conditional or unconditional security for smart grids in the absence of authenticated, secure communication. Method: The authors propose a novel spectral analysis attack that requires neither access to the private watermark signal nor a digital twin model; instead, it reconstructs system states and infers communication protocols by modeling and analyzing observable environmental noise—achieving zero-false-positive stealthy attacks. Contribution/Results: This is the first attack to fully bypass dynamic watermarking detection without prior knowledge and with minimal overhead. Experiments confirm that watermarking offers no security when communication links lack encryption and authentication, while under strong authenticated communication, watermarks become redundant and yield no tangible security benefit. The core contribution is the formal revelation that the security guarantee of dynamic watermarking is entirely contingent upon communication channel trustworthiness—not on the watermarking mechanism itself.
📝 Abstract
Previous research employing a conceptual approach with a digital twin has demonstrated that (noise-based) dynamic watermarking is incapable of providing unconditional security in smart electrical grid systems. However, the implementation of digital twins can be prohibitively costly or infeasible due to limited available data on critical infrastructure. In this study, we first analyze the spectral properties of dynamic watermarking and its associated protocol. Subsequently, we present a straightforward attack inspired by the digital twin method, which extracts and utilizes the grid noises and completely breaches the security of dynamic watermarking without requiring knowledge of the private watermarking signal. The attacker can fully expose the grid while evading detection by the controller. Our findings indicate that in the absence of secure and authenticated communications, dynamic watermarking offers neither conditional nor unconditional security. Conversely, when communication lines, sensors, and communicators are equipped with tamper-resistant and secure/authenticated links, dynamic watermarking becomes redundant for grid security.