IF YOU鈥橵E got a message to keep safe, look to the skies. You could use the afterglow of the big bang to make encryption keys 鈥� all you need is a radio telescope.
The security of many systems relies on generating large random numbers to act as keys to encrypt information. Computers can use algorithms to spawn these keys, but they aren鈥檛 truly random, so another computer armed with the same algorithm could potentially duplicate the key.
An alternative is to rely on physical randomness, like the weather, the thermal noise on a chip or the timing of someone鈥檚 keystrokes. Now Jeffrey Lee and Gerald Cleaver at Baylor University in Waco, Texas, have taken this to the extreme by suggesting we use the thermal radiation left over from the big bang 鈥� the cosmic microwave background.
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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鈥檚 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 (arxiv.org/abs/1511.02511).
鈥淎n adversary measuring the same patch of sky exactly the same way and at exactly the same time could not get exactly the same values,鈥� says Lee.
Mads Haahr of Trinity College Dublin in Ireland runs a website called random.org, which uses noise from weather to generate random numbers. He says the big issue with CMB encryption would be setting up a radio telescope to get a key.
Lee agrees this is not something individuals can do, and it might not offer better encryption than the weather. But, he says, 鈥渋t brings together two fields of study that don鈥檛 often cross-pollinate 鈥� early universe cosmology and cryptography鈥�.
This article appeared in print under the headline 鈥淓ncrypt secrets in the afterglow of the big bang鈥�
