A Quantum Random-Number Generator On Your Phone

Truly random numbers are surprisingly hard to generate, and are necessary for everyday digital security.

You might not think that it’s that hard to be random, but creating truly random numbers is quite difficult… and these digits underlie and protect almost every digital transaction we make. Most normal computers “are completely deterministic and are therefore not capable of creating truly random numbers,” as Physics World reports. They are, in other words, designed to do things repetitively, the antithesis of randomness. Cryptography systems generally rely on “pseudo random-number” generators, which are close to random but not completely, making them possible to crack. One recently revealed NSA backdoor involved a clandestine pattern “baked into” a Federally approved number generator, which effectively broke it.

One way to create random numbers is to measure random phenomena like the noise in an electronic circuit, but such processes are often unreasonably slow or expensive.

Now, however, researchers have created a quantum random generator–capable of producing long strings of digits that could create a theoretically unbreakable code–using low-cost electronic components including a cellphone camera. This is how it works, as Physics World notes:

The arXiv blog further explains:

Study co-author Bruno Sanguinetti, at the University of Geneva in Switzerland, told Physics World that the components of this generator could be fashioned into a chip that would cost a “couple of dollars” and could be put into mobile devices. “If there is a quantum technology that everyone will soon have, this is it,” he said. But Anthony Laing of the University of Bristol cautioned that “it might be possible to design certain hacks based on quantum states of light that have different noise characteristics, and the authors of this work will no doubt have methods for dealing with these.”

In case you’re curious, you can find your own quantum random number here, created by a server that measures “the quantum fluctuations of [a] vacuum.”

[Physics World / arXiv]