Simple Cracking of (Noise-Based) Dynamic Watermarking in Smart Grids

TL;DR

This paper demonstrates that noise-based dynamic watermarking in smart grids can be easily compromised with a simple attack, revealing its ineffectiveness without secure communication channels.

Contribution

The study provides a straightforward attack method that breaches dynamic watermarking security without needing private watermark information, challenging its effectiveness in real-world scenarios.

Findings

Dynamic watermarking can be fully breached by a simple noise-based attack.

Without secure, authenticated communication, watermarking offers no security benefits.

Secure communication channels render dynamic watermarking redundant for grid security.

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.