Privately detecting changes in unknown distributions

TL;DR

This paper introduces differentially private algorithms for change-point detection in data streams with unknown and smoothly changing distributions, addressing practical privacy concerns in sensitive applications.

Contribution

It develops novel private algorithms for change-point detection without requiring prior knowledge of distributions, including smoothly varying cases.

Findings

Algorithms effectively detect distribution changes while preserving privacy.

Experimental results demonstrate practical performance and accuracy.

Applicable to real-world sensitive data scenarios.

Abstract

The change-point detection problem seeks to identify distributional changes in streams of data. Increasingly, tools for change-point detection are applied in settings where data may be highly sensitive and formal privacy guarantees are required, such as identifying disease outbreaks based on hospital records, or IoT devices detecting activity within a home. Differential privacy has emerged as a powerful technique for enabling data analysis while preventing information leakage about individuals. Much of the prior work on change-point detection---including the only private algorithms for this problem---requires complete knowledge of the pre-change and post-change distributions. However, this assumption is not realistic for many practical applications of interest. This work develops differentially private algorithms for solving the change-point problem when the data distributions are unknown. Additionally, the data may be sampled from distributions that change smoothly over time, rather than fixed pre-change and post-change distributions. We apply our algorithms to detect changes in the linear trends of such data streams. Finally, we also provide experimental results to empirically validate the performance of our algorithms.