The Lava Lamps That Help Keep The Internet Secure
 

Video by Tom Scott.

At the headquarters of Cloudflare, in San Francisco, there's a wall of lava lamps: the Entropy Wall. They're used to generate random numbers and keep a good bit of the internet secure: here's how.

There also is another kit for generating random numbers, mentioned in the video: a radioactive source. Much less spectacular... :)

This is just a publicity stunt. From a technical point of view it's ridiculous.

Radioactive generators are also aimed at the credulous. Most, if not all, hardware generators are either directly quantum mechanical or indirectly tied to it through chaotic behavior.

Entropy sources don't actually have to be particularly random, they just have to be not entirely predictable. Spinning hard drives have timing uncertainties that come from turbulence and friction - much better than a lava lamp.