POV-Ray : Newsgroups : povray.pov4.discussion.general : Feature requests: true rand() and date() : Re: Feature requests: true rand() and date() Server Time
21 Feb 2024 23:05:07 EST (-0500)
  Re: Feature requests: true rand() and date()  
From: clipka
Date: 5 Jan 2009 00:15:00
Message: <web.49619630dfc337b2c38b01850@news.povray.org>
Warp <war### [at] tagpovrayorg> wrote:
> Nicolas Alvarez <nic### [at] gmailcom> wrote:
> > Timo Poikola wrote:
> > > First of all, it will be nice if the RNG is able to generate true random
> > > numbers.
> > Computers can't do that.
>   Actually that's not entirely true. For example see:
> http://en.wikipedia.org/wiki//dev/random

As far as I can see, even these are, technically speaking, not random after all.
They're just a *very* complex PRNG (basically using the whole system for
pseudorandom feedback). I'd expect the generated number sequences to pass all
known tests for randomness though, so in practice it should be way sufficient.
For cryptographic applications that is, because something like POV has totally
different requirements for a (P)RNG.

It happens that I've just recently stumbled across an article in a computer
magazine about RNGs and PRNGs; it actually includes a description of an
interesting DIY hardware RNG, exploiting the thermal noise from a webcam CCD.

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