Secure Distributed Consensus Estimation under False Data Injection Attacks: A Defense Strategy Based on Partial Channel Coding
Jiahao Huang, Marios M. Polycarpou, Wen Yang, Fangfei Li, Yang Tang
TL;DR
This work addresses the security of distributed consensus estimation in CPS under stealthy false data injection when an attacker can compromise a subset of communication channels. It derives necessary and sufficient conditions for when such attacks can diverge the estimation error while remaining undetected, for both full-channel and partial-channel scenarios. To defend against these attacks, the paper proposes two strategies: (i) detection based on the Euclidean distance between local state estimates, and (ii) a coding-based protection using time-varying, synchronized encoding matrices $M_{ij}(k)$ to protect channel transmissions; it also provides an allocation procedure to balance security against coding costs. A key finding is that the Euclidean-distance detector covers many vulnerabilities, while the coding scheme can fully restore security if the encoding remains confidential; their combination reduces encoding requirements through a joint protection framework. The results are supported by numerical simulations on a 30-node network, illustrating the approach’s practical relevance for secure, scalable distributed estimation in resource-limited sensor networks.
Abstract
This article investigates the security issue caused by false data injection attacks in distributed estimation, wherein each sensor can construct two types of residues based on local estimates and neighbor information, respectively. The resource-constrained attacker can select partial channels from the sensor network and arbitrarily manipulate the transmitted data. We derive necessary and sufficient conditions to reveal system vulnerabilities, under which the attacker is able to diverge the estimation error while preserving the stealthiness of all residues. We propose two defense strategies with mechanisms of exploiting the Euclidean distance between local estimates to detect attacks, and adopting the coding scheme to protect the transmitted data, respectively. It is proven that the former has the capability to address the majority of security loopholes, while the latter can serve as an additional enhancement to the former. By employing the time-varying coding matrix to mitigate the risk of being cracked, we demonstrate that the latter can safeguard against adversaries injecting stealthy sequences into the encoded channels. Hence, drawing upon the security analysis, we further provide a procedure to select security-critical channels that need to be encoded, thereby achieving a trade-off between security and coding costs. Finally, some numerical simulations are conducted to demonstrate the theoretical results.
