The Capacity of Single-Server Weakly-Private Information Retrieval
Journal article, 2021

A private information retrieval (PIR) protocol guar- antees that a user can privately retrieve files stored in a database without revealing any information about the identity of the requested file. Existing information-theoretic PIR proto- cols ensure perfect privacy, i.e., zero information leakage to the servers storing the database, but at the cost of high download. In this work, we present weakly-private information retrieval (WPIR) schemes that trade off perfect privacy to improve the download cost when the database is stored on a single server. We study the tradeoff between the download cost and information leakage in terms of mutual information (MI) and maximal leak- age (MaxL) privacy metrics. By relating the WPIR problem to rate-distortion theory, the download-leakage function, which is defined as the minimum required download cost of all single- server WPIR schemes for a given level of information leakage and a fixed file size, is introduced. By characterizing the download- leakage function for the MI and MaxL metrics, the capacity of single-server WPIR is fully described.

single server

capacity

information leakage

information-theoretic privacy

Private information retrieval

Author

Hsuan Yin Lin

Simula UiB

Siddhartha Kumar

Simula UiB

Eirik Rosnes

Simula UiB

Alexandre Graell I Amat

Chalmers, Electrical Engineering, Communication, Antennas and Optical Networks, Communication Systems

Simula UiB

Eitan Yaakobi

Technion – Israel Institute of Technology

IEEE Journal on Selected Areas in Information Theory

2641-8770 (eISSN)

Vol. 2 1 415-427

Rethinking Distributed Storage for Data Storage and Wireless Content Delivery

Swedish Research Council (VR) (2016-04253), 2016-01-01 -- 2019-12-31.

Subject Categories

Other Computer and Information Science

Information Studies

Communication Systems

Areas of Advance

Information and Communication Technology

DOI

10.1109/JSAIT.2021.3056327

More information

Latest update

1/12/2022