This is scientific American's 60 second science.

I'm Christopher Intagiyata.

Random numbers are hugely important for modern computing.

They are used to encrypt credit card numbers and emails to inject randomness into online gaming and to simulate super complex phenomena like protein folding or nuclear fission.

But here's the dirty secret. A lot of these so-called random numbers are not truly random.

They're actually what's known as pseudo-random numbers, generated by algorithms.

Think, for example, of generating random numbers by rolling dice.

If you know the number of dice, it's simple to figure out something about the realm of possible random numbers,

thus putting probabilistic limits on the randomness.

But truly random numbers can be generated

through quantum mechanical processes. So researchers built a photonic chip, that's a computer chip

that uses photons instead of electrons.

The chip has two lasers.

One shoots continuously, the other pulses at regular intervals.

And each time the two lasers meet, the interference between the light beams is random

thanks to the rules of quantum mechanics. The chip then digitizes that random

signal and voila a quantum random number generator. The study is in the journal Optica. It's not the first time this sort of thing's been built, but compared to old prototypes, this chip is much smaller, a sixth the size of a penny, and it works at high speeds too. Meaning small and

fast enough for a smartphone? The researchers say that's an entirely predictable

outcome. Thanks for listening.

For Scientific American 60 Second Science,

I'm Christopher in Dunyata.