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

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Zvika Brakerski, Paul F. Christiano, Urmila Mahadev, Umesh V. Vazirani, Thomas Vidick

Published: 2021, Last Modified: 05 May 2026J. ACM 2021EveryoneRevisionsBibTeXCC BY-SA 4.0
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 that 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.