Jerry Leichter wrote:

> At ThinkGeek, you can now, for only $6.99, buy yourself a USB-powered
> mini lava lamp (see 
> "All you need" is some way to watch the thing - perhaps a USB camera -
> and some software to extract random bits.  (This isn't *really* a lava
> lamp - the lamp is filled with a fluid containing many small reflective
> plastic chips, lit from below by a small incandescent bulb which also
> generates the heat that keeps the fluid circulating.  From any given
> vantage point, you get flashes as one of the plastic chips gets into
> just the right position to give you a reflected view of the bulb.  These
> should be pretty easy to extract, and should be quite  random.  Based on
> observation, the bit rate won't be very high - a bit every couple of
> seconds - though perhaps you can use cameras at a couple of vantage
> points.  Still, worth it for the bragging rights.)

Does anyone know of a cheap USB random number source?

As a meandering comment, it would be extremely good for us if we had
cheap pocket random number sources of arguable quality [1].

I've often thought that if we had an open source hardware design of
a USB random number generator ... that cost a few pennies to add
onto any other USB toy ... then we could ask the manufacturers to
throw it in for laughs.  Something like a small mountable disk that
returns randoms on every block read, so the interface is trivial.

Then, when it comes time to generate those special keys, we could
simply plug it in, run it, clean up the output in software and use
it.  Hey presto, all those nasty software and theoretical
difficulties evaporate.


[1] the competitive process and a software clean-up would sort out
any quality issues.

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