Quantum Private Queries: security analysis

TL;DR

This paper analyzes the security of a quantum private query protocol that enables private database searches while ensuring data privacy through quantum information-disturbance tradeoffs.

Contribution

It provides a detailed security analysis of the Quantum Private Query protocol, highlighting its cheat sensitivity and privacy guarantees.

Findings

The protocol detects privacy violations via quantum disturbance.

It ensures data privacy independent of database size.

The security relies on information-disturbance tradeoffs.

Abstract

We present a security analysis of the recently introduced Quantum Private Query (QPQ) protocol. It is a cheat sensitive quantum protocol to perform a private search on a classical database. It allows a user to retrieve an item from the database without revealing which item was retrieved, and at the same time it ensures data privacy of the database (the information that the user can retrieve in a query is bounded and does not depend on the size of the database). The security analysis is based on information-disturbance tradeoffs which show that whenever the provider tries to obtain information on the query, the query (encoded into a quantum system) is disturbed so that the person querying the database can detect the privacy violation.