A Cryptographic Test of Quantumness and Certifiable Randomness from a Single Quantum Device

TL;DR

This paper introduces a new model for testing untrusted quantum devices using a single device and classical verifier, providing protocols for verifying quantumness and generating certifiable randomness based on post-quantum cryptographic primitives.

Contribution

It proposes a novel model for single-device quantum testing and develops cryptographic protocols for verification and randomness generation using trapdoor claw-free functions.

Findings

Protocols for efficient classical verification of quantum devices

Construction of cryptographic primitives based on LWE hardness

Certifiable randomness from a single untrusted quantum device

Abstract

We consider a new model for the testing of untrusted quantum devices, consisting of a single polynomial-time bounded quantum device interacting with a classical polynomial-time verifier. In this model we propose solutions to two tasks - a protocol for efficient classical verification that the untrusted device is "truly quantum," and a protocol for producing certifiable randomness from a single untrusted quantum device. Our solution relies on the existence of a new cryptographic primitive for constraining the power of an untrusted quantum device: post-quantum secure trapdoor claw-free functions which must satisfy an adaptive hardcore bit property. We show how to construct this primitive based on the hardness of the learning with errors (LWE) problem.