[NCLUG] My attempts using /dev/random...

James DeWitt jdewitt at verinet.com
Mon Apr 14 17:34:25 MDT 2008


On Monday 14 April 2008 4:26:06 pm Chad Perrin wrote:
> On Mon, Apr 14, 2008 at 01:09:26AM -0600, Sean Reifschneider wrote:
> > >Unfortunately, the harsh truth is that both /dev/random and /dev/urandom
> > >are flawed.  They're PRNGs -- they do not provide *true* random numbers.
> >
> > /dev/random on Linux is *NOT* simply a PRNG.  Which is why it took nearly
> > a day to gather enough entropy for 1.6MB worth of /dev/random output. See
> > the comments at the top of the /dev/random driver source for information
> > about how it collects entropy, or it's approximation of it.
>
> The reason it took so long involved collecting seed data.  Whether or not
> you consider it a PRNG really depends on whether you consider the number
> generating algorithm to qualify something as a PRNG, regardless of
> seeding behavior.

Interesting.  Please explain the algorithm that Linux uses for /dev/random 

Thanks,
JD



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