From: "Mauricio Fernández" <batsman.geo@...>
Date: 2003-02-27T07:17:59+09:00
Subject: Re: Objectify the mersenne twister in 1.8?

On Thu, Feb 27, 2003 at 05:36:36AM +0900, gabriele renzi wrote:
> il Wed, 26 Feb 2003 14:25:12 +0000 (UTC),
> <bbense+comp.lang.ruby.Feb.26.03@telemark.slac.stanford.edu> ha
> scritto::
> 
> >
> >_ As a side note, it's an open question whether there is 
> >ANY prng that is secure for cryptography. All you can do
> >is show that a given prng is not suitable for cryptography. 
> >There is some very interesting work happening in this 
> >area based on the Yarrow paper by Bruce Schneier
> >and John Kelsey. The EGADS system provided by 
> >
> >http://www.securesoftware.com/auditing_tools_download.htm
> 
> 
> thanks for the hint! 
> 
> Acually I think having OS-level entropy gathering, and thus getting
> ability to provide good random numbers is a must for crypto-level
> randomness .
> 
> Freebsd 5.0 (maybe OpenBSD too?) and linux <insert recent version
> here>  support yarrow for random, and they could even use hardware
> PRNG devices, that's why  I'd like to exploit this features, even if
> missing some portability.

Is reading /dev/random (under Linux) enough to assure the random numbers
are cryptographically secure?

man urandom

    The  random  number  generator gathers environmental noise from
    device drivers and other sources into an entropy pool.  The generator
    also keeps an estimate of the number of bit of the  noise  in  the
    entropy pool.  From this entropy pool random numbers are created.
    
    When  read,  the /dev/random device will only return random bytes
    within the estimated number of bits of noise in the entropy pool.
    /dev/random should be suitable for uses that need very high
    quality  randomness  such as one-time pad or key generation.
    When the entropy pool is empty, reads to /dev/random will block
    until additional environmental noise is gathered.

> Oh, and someone feels that Intel saying they put a "pure RNG" in their
> cpu is hype? ;)

If they got something like the Pentium division bug to bite randomly
(by quantum effects or the like) it'd do the trick, wouldn't it?
The chips run so hot it must be easy to gather some entropy there...
 

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