# Improved and Formal Proposal for Device Independent Quantum Private Query

## TL;DR

This paper introduces a fully device-independent quantum private query scheme using EPR pairs, employing self-testing techniques for shared entanglement and measurements, with formal security analysis against dishonest parties.

## Contribution

It presents the first full DI-QPQ protocol leveraging EPR pairs and self-testing of measurement operators, enhancing security in quantum private queries.

## Key findings

- Achieves full device independence in QPQ using EPR pairs.
- Provides formal security bounds against cheating.
- Demonstrates the feasibility of self-testing in DI-QPQ protocols.

## Abstract

In this paper, we propose a novel Quantum Private Query (QPQ) scheme with full Device-Independent certification. To the best of our knowledge, this is the first time we provide such a full DI-QPQ scheme using EPR-pairs. Our proposed scheme exploits self-testing of shared EPR-pairs along with the self-testing of projective measurement operators in a setting where the client and the server do not trust each other. To certify full device independence, we exploit a strategy to self-test a particular class of POVM elements that are used in the protocol. Further, we provide formal security analysis and obtain an upper bound on the maximum cheating probabilities for both the dishonest client as well as the dishonest server.