Cloudflare’s Lava Lamps
When you walk into the San Francisco office of the cloud network and security firm Cloudflare, you’re greeted by a receptionist–and a giant wall of 100 lava lamps. It isn’t just a throwback to the 1960s. The lava lamps act as a random number generator, helping to encrypt the requests that go through Cloudflare, which make up 10% of all internet requests.
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Cloudflare turns the “Wall of Entropy” into encryption using a camera that photographs the wall every millisecond of every day of the year. Any one of the company’s systems can turn the display of pixels–which changes based on a multitude of factors, like the movement of the lava, the inclusion of anyone who’s walking by, and the shifting daylight–into random numbers.
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In London, they use dual pendulums. While a single pendulum swinging back and forth is very predictable, mathematicians have shown that if you take a pendulum and hang another pendulum from it, you’ll create a system that no one has figured out how to model.
This was done back at SGI in the late 90's: https://en.wikipedia.org/wiki/Lavarand
You could actually see the webcam back then too