2020/01/23 by Hsuan-Yin Lin, Siddhartha Kumar, Lin, Hsuan-Yin +7
Computer Science · #Cryptography and Data Security #FOS: Computer and information sciences #Information Theory (cs.IT) #Internet Traffic Analysis and Secure E-voting #Privacy-Preserving Technologies in Data
paper · pdf · doi:10.48550/arxiv.2001.08727
openalex publication_date 2020/01/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
A private information retrieval (PIR) protocol guarantees 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 protocols 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 leakage (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.