Database Matching Under Noisy Synchronization Errors

TL;DR

This paper develops a unified framework for database matching that accounts for obfuscation and synchronization errors, providing theoretical conditions for successful re-identification under noisy, time-indexed data.

Contribution

It introduces new algorithms and theoretical conditions for matching databases with synchronization errors and obfuscation, expanding understanding of privacy risks in time-indexed data.

Findings

Derived necessary and sufficient conditions for successful database matching.

Proposed replica detection and seeded deletion detection algorithms.

Analyzed the impact of adversarial deletion, seedless matching, and zero-rate regimes.

Abstract

The re-identification or de-anonymization of users from anonymized data through matching with publicly available correlated user data has raised privacy concerns, leading to the complementary measure of obfuscation in addition to anonymization. Recent research provides a fundamental understanding of the conditions under which privacy attacks, in the form of database matching, are successful in the presence of obfuscation. Motivated by synchronization errors stemming from the sampling of time-indexed databases, this paper presents a unified framework considering both obfuscation and synchronization errors and investigates the matching of databases under noisy entry repetitions. By investigating different structures for the repetition pattern, replica detection and seeded deletion detection algorithms are devised and sufficient and necessary conditions for successful matching are derived. Finally, the impacts of some variations of the underlying assumptions, such as the adversarial deletion model, seedless database matching, and zero-rate regime, on the results are discussed. Overall, our results provide insights into the privacy-preserving publication of anonymized and obfuscated time-indexed data as well as the closely related problem of the capacity of synchronization channels.