Cooperative Local Differential Privacy: Securing Time Series Data in Distributed Environments

TL;DR

This paper introduces Cooperative Local Differential Privacy (CLDP), a novel method that enhances privacy in time series data by distributing noise among users, preventing privacy breaches while maintaining data utility.

Contribution

The paper proposes a new cooperative noise generation mechanism for local differential privacy that improves privacy guarantees and scalability for real-time time series data.

Findings

CLDP effectively cancels out noise during data aggregation, preserving data utility.

The method enhances privacy protection against time-window-based attacks.

CLDP scales well for large, real-time datasets.

Abstract

The rapid growth of smart devices such as phones, wearables, IoT sensors, and connected vehicles has led to an explosion of continuous time series data that offers valuable insights in healthcare, transportation, and more. However, this surge raises significant privacy concerns, as sensitive patterns can reveal personal details. While traditional differential privacy (DP) relies on trusted servers, local differential privacy (LDP) enables users to perturb their own data. However, traditional LDP methods perturb time series data by adding user-specific noise but exhibit vulnerabilities. For instance, noise applied within fixed time windows can be canceled during aggregation (e.g., averaging), enabling adversaries to infer individual statistics over time, thereby eroding privacy guarantees. To address these issues, we introduce a Cooperative Local Differential Privacy (CLDP) mechanism that enhances privacy by distributing noise vectors across multiple users. In our approach, noise is collaboratively generated and assigned so that when all users' perturbed data is aggregated, the noise cancels out preserving overall statistical properties while protecting individual privacy. This cooperative strategy not only counters vulnerabilities inherent in time-window-based methods but also scales effectively for large, real-time datasets, striking a better balance between data utility and privacy in multiuser environments.