Improving Utility of Differentially Private Mechanisms through Cryptography-based Technologies: a Survey

TL;DR

This survey reviews how cryptography-based technologies like anonymous communication and homomorphic encryption can enhance the utility of differentially private mechanisms, highlighting current achievements and limitations.

Contribution

It systematically summarizes methods combining cryptography with differential privacy to improve utility, and discusses cryptographic hardness results impacting privacy mechanisms.

Findings

Cryptography techniques can significantly improve differential privacy utility.

Homomorphic encryption enables privacy-preserving data analysis with better utility.

Certain utility improvements are proven impossible due to cryptographic hardness results.

Abstract

Due to successful applications of data analysis technologies in many fields, various institutions have accumulated a large amount of data to improve their services. As the speed of data collection has increased dramatically over the last few years, an increasing number of users are growing concerned about their personal information. Therefore, privacy preservation has become an urgent problem to be solved. Differential privacy as a strong privacy preservation tool has attracted significant attention. In this survey, we focus on improving utility of between differentially private mechanisms through technologies related to cryptography. In particular, we firstly focus on how to improve utility through anonymous communication. Then, we summarize how to improve utility by combining differentially private mechanisms with homomorphic encryption schemes. Next, we summarize hardness results of what is impossible to achieve for differentially private mechanisms' utility from the view of cryptography. Differential privacy borrowed intuitions from cryptography and still benefits from the progress of cryptography. To summarize the state-of-the-art and to benefit future researches, we are motivated to provide this survey.