Totally Random

Credit: Quantinuum

To keep cryptocurrency transactions fair and safe, the technologies that underpin them rely on a steady stream of big random numbers. But there’s always the risk that a bad actor could hack these blockchain systems and sneak in some not-so-random numbers. That might allow them to unfairly get more profit from processing transactions or even take control of the entire blockchain. One way to harden these systems might be to use quantum computers to generate the random numbers.

UT Austin computer science professor Scott Aaronson proposed a protocol called certified randomness that ensures the number you get back from a quantum computer really is random and couldn’t have been spoofed using a classical computer. His collaborators at Quantinuum, JPMorganChase and two national labs recently demonstrated the protocol using a 56-qubit quantum computer. The breakthrough, reported in the journal Nature, may be the first demonstration of a truly practical and real-world application of quantum computers.

“ One way to harden these systems might be to use quantum computers.”

One key to the approach is speed. Researchers repeatedly feed the quantum computer challenges that it must quickly solve, ones that even the world’s most powerful classical supercomputer would need a lot of time to solve and which the quantum computer can only solve by picking one of many possible solutions at random. The answer coming back very fast ensures the result was not spoofed by a bad actor. The other key is to use a classical supercomputer to mathematically verify that the result is genuinely random.

“Building upon the original protocol and realizing it is a first step toward using quantum computers to generate certified random bits for real-world applications,” Aaronson said.