jeff sisson's blog (email me)

Good random numbers

29 Jun 2014

I’m struck by this piece of advice offered by GNUPG, a piece of software used in cryptography:

We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.

The idea that random keystrokes help to make a “good random number” is pleasantly analog. A connoiseur might look at a random number and deduce that it was generated with an old computer, or a computer with a sticky keyboard, or a computer that was infrequently used.

When first encountering computers in elementary school, I remember a kid in my class who invariably tried to convince other kids that his random keystrokes, made while the computer started up, were the only thing that allowed the computer to startup at all. It’s wonderful that this turns out to be, in a twisted way, true!


I’m reminded of a favorite (fake) theory about ancient greek pottery:

A pot or vase could be “read” like a gramophone record or phonograph cylinder for messages from the past, sounds encoded into the turning clay as the pot was thrown.

The underyling myth notwithstanding, it’s somehow easy to imagine ancient potters choosing to make pottery in purpose-built rooms because it “sounds better” — that the ambience of the room somehow makes its way into the clay form. In the same vein, you might imagine someone who downloads music mp3 “naked” or “while on vacation”, on the theory that it sounds better that way.

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