The first truly random number generator built: uses quantum entanglement

If God does play dice with the universe, scientists have created “the best random number generator that the universe allows.” It works by measuring entangled photons and broadcasting the random results publicly.

The National Institute of Standards and Technology (NIST) and the University of Colorado Boulder announced they’ve built “the first random number generator.”

The system, called the Colorado University Randomness Beacon (CURBy), produces verifiable random numbers for public use.

It beats classical computers that can only create pseudorandom numbers – they can be manipulated or predicted by someone with enough knowledge of the algorithm. Even a coin flip can be rigged or predicted.

“True randomness is something that nothing in the universe can predict in advance,” said Krister Shalm, a physicist at the NIST. “Even if a random number generator used seemingly random processes in nature, it would be hard to verify that those numbers are truly random.”

CURBy is powered by the NIST-run Bell test, which produces random results by measuring pairs of entangled photons, “whose properties are correlated even when separated by vast distances.”

The researchers explain that when they measure an individual particle, the outcome is random, “but the properties of the pair are more correlated than classical physics allows, enabling researchers to verify the randomness.” Albert Einstein referred to this quantum nonlocality as “spooky action at a distance.”

NIST assures the random number generation service is the first to use quantum nonlocality as a source of its numbers, and it is “the most transparent source of random numbers to date”, because the results are certifiable and traceable to a greater extent than ever before.

“If God does play dice with the universe, then you can turn that into the best random number generator that the universe allows,” Shalm said.

Quantum mechanics, unlike computer algorithms, are inherently random. Einstein didn’t believe this, famously saying, “God does not play dice with the universe,” but has since been proven wrong.

The researchers hope a public source of randomness will be useful for selecting jury candidates, assigning resources through a public lottery, and anywhere where an independent random number generation would be useful. The service can be accessed on the CURBy website. It has a public API for the use of randomness in applications.

NIST built the world’s “first source of true randomness” in 2018, after completing experimental Bell tests in 2015. The breakthrough required months of setup to run for a few hours, and it took a lot of time to collect enough data to generate 512 random bits. Since then, researchers have spent the past few years making a robust solution.

“In its first 40 days of operation, the protocol produced random numbers 7,434 times out of 7,454 attempts, a 99.7% success rate.”

Now, CURBy is the first publicly available service. Shalm and his team published the results of their work in Nature.