Dimension Reduction via Random Projection for Privacy in Multi-Agent Systems
Puspanjali Ghoshal, Ashok Singh Sairam
TL;DR
This work tackles inference privacy in Multi-Agent Systems by introducing a compression-based sanitization that achieves a principled utility-privacy trade-off via robust concepts. The core method, neuronal random projection (NRP), uses per-instance random projection matrices constrained by a Frobenius-norm bound to preserve utility while increasing privacy, and it achieves distance-preserving properties comparable to standard random projection with lower computational cost. The authors formalize utility and privacy as $u_i(T)=\cos(\mathbf{y_i}, T(\mathbf{y_i}))$ and $p_i(T)=1-u_i(T)$, derive $0<||A_i||_F\le \min\{t,2\epsilon_i+\delta\}$ bounds, and establish robustness concepts guiding sanitization. Empirical results on real hospital and synthetic data show NRP outperforms BRP, PCA, and ASUP across breach count, displacement, and resemblance, indicating strong privacy protection with retained utility in MAS settings. The work suggests practical, scalable privacy mechanisms for MAS and points to future work on active adversaries and dynamic agent populations.
Abstract
In a Multi-Agent System (MAS), individual agents observe various aspects of the environment and transmit this information to a central entity responsible for aggregating the data and deducing system parameters. To improve overall efficiency, agents may append certain private parameters to their observations. For example, in a crowd-sourced traffic monitoring system, commuters might share not only their current speed, but also sensitive information such as their location to enable more accurate route prediction. However, sharing such data can allow the central entity or a potential adversary to infer private details about the user, such as their daily routines. To mitigate these privacy risks, the agents sanitize the data before transmission. This sanitization inevitably results in a loss of utility. In this work, we formulate the problem as a utility-privacy trade-off and propose a novel compression-based approach leveraging the notion of robust concepts to sanitize the shared data. We further derive a bound on the norm of the compression matrix required to ensure maximal privacy while satisfying predefined utility constraints.
