Certified randomness using a trapped-ion quantum processor

In many applications including cryptography, lotteries, and auditing, having randomness that can be trusted by all parties is crucial. Generation of certified randomness is impossible solely by classical computation, but possible with quantum devices. Utilizing beyond-classical random circuit sampling, we demonstrate certified randomness generation that is secure against attack from the most powerful supercomputers. Our protocol leverages the classical hardness of recent random circuit sampling demonstrations: a client generates quantum "challenge" circuits, sends them to an untrusted quantum server over the network to execute, and verifies the server's results. We prove the security of our protocol in several adversarial models, including a complexity theoretic proof. Our certified randomness experiment demonstrates a step towards the practical applicability of today's quantum computers.