Believe it or not, it’s actually quite difficult to generate random numbers on computers and microcontrollers. I’m talking about true random. A lot of the randomness computers use isn’t random at all, it’s predictive (or pseudo random). Difficult, but still predictive. It’s important when doing cryptographic functions to use a good random source.
So f4grx decided to build a random circuit and do some analysis on it. The circuit design is built around the idea of using an open collector on a transistor. What’s essentially going to happen is tiny electrical noise in the air is going to cause the circuit to produce 1′s and 0′s which then can be used to plot random.
Interesting read. Check out f4grx’s experience.