A Wall of Lava Lamps That Generate Enough Randomness to Help Keep the Internet Secure

In a random, non-sponsored episode of Amazing Places, host Tom Scott visited the San Francisco headquarters of Cloudflare, a reverse proxy company that improves website performance and security. Upon entering the office, Scott encountered a beautiful wall of colorful lava lamps. While pretty to look at, these lamps are actually used to generate cryptographic entropy in generating random numbers. The company videotapes the lamps and turns the footage into a stream of “random, unpredictable bytes” to generate secure encryption keys.

In short, these folks deal with a lot of encrypted Internet traffic, so they need a lot of random numbers. It is possible to write code that will simulate randomness, and that’s good enough for a lot of uses, but in theory, those numbers could be predicted. They’re just being generated by code, so the servers here have to get their randomness from an external and entirely unpredictable source. …hence lava lamps.