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Date: Tue, 24 May 2005 18:18:18 -0700
From: Kris Kennaway <kris@obsecurity.org>
To: Nicolas Blais <nb_root@videotron.ca>
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Cc: freebsd-questions@freebsd.org
Subject: Re: srandomdev() vs srandom() vs arc4random()
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On Tue, May 24, 2005 at 09:13:45PM -0400, Nicolas Blais wrote:
> I'm developping a software that uses random generated numbers. Since thes=
e=20
> numbers must be as "chaotic" as possible, I'm using srandomdev(). My prob=
lem=20
> is that I'm only able to compile my software on *BSD and certain distros =
of=20
> Linux seem to be stripped of the call. This forces me to rely on=20
> srandom(time(NULL)) for portability.
>=20
> I would like to know how "random" (that is, how inprobable a pattern will=
=20
> appear) if I use srandom(time(NULL)) instead of srandomdev().
>
> Also, would arc4random() be any better in getting the least pattern creat=
ion.

arc4random() should produce higher quality randomness, although
srandom() may be good enough for your needs.

> Finally, is there is a way to check if the call srandomdev() exists on ot=
her=20
> OSes?

Sure, compile a test app in your configure script :-)

Kris
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