Two-Server Private Information Retrieval with Optimized Download Rate and Result Verification

TL;DR

This paper introduces two-server PIR schemes that ensure privacy, correctness, and high download efficiency, even when servers may act dishonestly, with various security guarantees and verification methods.

Contribution

It proposes novel two-server PIR schemes with optimized download rates and result verification, addressing dishonest server behavior with information-theoretic and computational security.

Findings

Achieved high download rates in PIR with dishonest servers

Developed schemes with public and private verification keys

Ensured information-theoretic privacy and correctness

Abstract

Private Information Retrieval (PIR) schemes allow a client to retrieve any file of interest, while hiding the file identity from the database servers. In contrast to most existing PIR schemes that assume honest-but-curious servers, we study the case of dishonest servers. The latter provide incorrect answers and try to persuade the client to output the wrong result. We introduce several PIR schemes with information-theoretic privacy and result verification for the case of two servers. Security guarantees can be information-theoretical or computational, and the verification keys can be public or private. In this work, our main performance metric is the download rate.