The Big Bang that created the Universe left traces of itself everywhere—an afterglow known as the cosmic microwave background (CMB). You’ve probably never thought to ask whether there’s a practical use for the CMB, but lo and behold, cosmologists found it: data encryption.


Many computer algorithms have been written to generate the large, random encryption keys we use to secure information, but this method comes with an inherent risk: if the algorithm is leaked, a key might be duplicated. That’s why some security researchers have turned to natural processes with an inherently random element—weather phenomena, for instance—as a safer source of random numbers.

But two cosmologists at Baylor University in Texas—perhaps feeling that their field needed an injection of Earthly relevance—have now come up with a rather out-of-this-world number generator. New Scientist explains how a radio telescope’s measurements of the oldest light in the universe might help keep our emails safe:


There are several ways to extract numbers from the CMB. For example, you could divide a patch of sky into pixels and measure the strength of the CMB’s radio signal, which is never duplicated exactly. Over time, each pixel would generate a string of different strengths, which are just numbers. Putting the strings together gets you a very large random number.

“An adversary measuring the same patch of sky exactly the same way and at exactly the same time could not get exactly the same values,” says Lee.

Of course, to get your hands on one of these astronomically unbreakable encryption keys, you’ll need a radio telescope, which makes this method a tad impractical for everyday applications. Then again, if you’re a SETI group hoping to keep humanity’s latest communications with intergalactic beings under wraps, I suppose this could be pretty handy. Wait, what?

[Read a pre-print of the study on arXiv h/t New Scientist]

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