The method uses photons to generate a string of random ones and zeros, and leans on the laws of physics to prove that these strings are truly random, rather than merely posing as random. The researchers say their work could improve digital security and cryptography.

The challenge for existing random number generators is not only creating truly random numbers, but proving that those numbers are random. "It's hard to guarantee that a given classical source is really unpredictable," says Peter Bierhorst, a mathematician at the National Institute of Standards and Technology (NIST), where this research took place. "Our quantum source and protocol is like a fail-safe. We're sure that no one can predict our numbers."

For example, random number algorithms often rely on a source of data which may ultimately prove predictable, such as atmospheric noise. And however complex the algorithm, it's still applying consistent rules. Despite these potential imperfections, these methods are relied on in the day-to-day encryption of data.