Privacy Preservation for Statistical Input in Dynamical Systems
Le Liu, Yu Kawano, Ming Cao
TL;DR
The paper addresses privacy preservation for stochastic inputs in linear dynamical systems by introducing a Wasserstein-based adjacency to capture distribution-level differences between inputs. It develops a Gaussian-mechanism framework that leverages two key lemmas linking symmetrized KL divergence to ${\mathcal{W}}_2$ and bounding outputs under affine mappings, yielding a practical condition on the noise covariance ${\Sigma}_{V_t}$ to ensure $(0,\delta)$-DP for Adj$_2^c$. A specialized result for publicly known initial states reduces conservatism, and a building-automation example demonstrates that occupancy-related privacy can be protected while quantifying the trade-off between privacy (via $\delta$) and utility. The work advances privacy in networked control by treating privacy of probabilistic inputs, not just deterministic data, and provides a concrete noisy-data design strategy for DP in discrete-time LTI systems.
Abstract
This paper addresses the challenge of privacy preservation for statistical inputs in dynamical systems. Motivated by an autonomous building application, we formulate a privacy preservation problem for statistical inputs in linear time-invariant systems. What makes this problem widely applicable is that the inputs, rather than being assumed to be deterministic, follow a probability distribution, inherently embedding privacy-sensitive information that requires protection. This formulation also presents a technical challenge as conventional differential privacy mechanisms are not directly applicable. Through rigorous analysis, we develop strategy to achieve $(0, δ)$ differential privacy through adding noise. Finally, the effectiveness of our methods is demonstrated by revisiting the autonomous building application.
