Practical Private Information Retrieval: Querying Databases Without Revealing Your Interests

Speaker: Dr. Mingxun Zhou
Assistant Professor
Department of Computer Science and Engineering
The Hong Kong University of Science and Technology

Title: Practical Private Information Retrieval: Querying Databases Without Revealing Your Interests

Date: Monday, 16 November 2026

Time: 4:00pm - 5:00pm

Venue: Lecture Theater F (Leung Yat Sing Lecture Theater), near lift 25/26, HKUST

Abstract:

When we search for information online, our queries can reveal sensitive details about our interests and intentions, which can include sensitive information. Can we retrieve information without the external observer knowing what we are looking for?

This talk introduces private information retrieval (PIR), a cryptographic technique for hiding which database item a user requests. Starting with examples, we will explain what privacy means in this setting, why simply encrypting a query is not enough, and what makes private queries computationally expensive. We will then explore a recently developed new model named preprocessing PIR. We will introduce Piano (IEEE S&P 2024) and our recent work, Multilevel PIR (IEEE S&P 2027), showing how these connected ideas support fast private queries on large databases. We will conclude with connections to private search and AI applications. The talk is intended for a general CS audience, and no prior knowledge of cryptography is required.

Biography:

Dr. Mingxun Zhou is an Assistant Professor at the Hong Kong University of Science and Technology. He received his Ph.D. from Carnegie Mellon University and his bachelor’s degree from Peking University. His research focuses on algorithm design and system implementation in applied cryptography, data security and privacy, and AI governance. His work addresses sensitive data processing, provenance of AI-generated content, and auditing of AI services. He has published 20 papers at leading conferences including IEEE S&P, ACM CCS, and Eurocrypt, and has served on the program committees of ACM CCS and Eurocrypt.