: Cosmic Cryptography https://briankoberlein.com/2015/11/30/cosmic-cryptology/
Often “random” numbers are only pseudo-random. They look like random numbers, but use a particular algorithm to simulate randomness.
To get better random numbers, you can use thermal fluctuations in your computer, or noise in weather data. Or, as in the case of a new paper,
data from the cosmic microwave background. It might seem like the CMB is a really bad choice. After all, it can be seen by everyone, so if
you use CMB data to create a random number why can’t someone else get the same number? But it turns out that’s not a problem.
The basic idea is to take a patch of sky and measure the distribution of energy from the CMB, specifically what’s known as the power spectrum.
That spectrum is then compared to the theoretical ideal, and the difference creates a random number. Even if someone measured exactly the same
patch of sky, they wouldn’t get the exact same result, and therefore wouldn’t get the same number. While the authors use the CMB as an example,
they point out a similar method could be used to generate random numbers from the 21 centimeter line, supernova remnants, radio galaxies and
other astrophysical phenomena. All you need is a basic radio telescope, and you have a random number generator.
It’s not likely that this astrophysical method is any better than what we use now. Thermal variations and weather patterns are pretty random
as it is. But it’s an interesting idea to use the secrets of the universe to keep your own secrets.