Date: Tue, 24 May 2005 18:18:18 -0700 From: Kris Kennaway <kris@obsecurity.org> To: Nicolas Blais <nb_root@videotron.ca> Cc: freebsd-questions@freebsd.org Subject: Re: srandomdev() vs srandom() vs arc4random() Message-ID: <20050525011818.GA7992@xor.obsecurity.org> In-Reply-To: <200505242113.54226.nb_root@videotron.ca>
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[-- Attachment #1 --] On Tue, May 24, 2005 at 09:13:45PM -0400, Nicolas Blais wrote: > I'm developping a software that uses random generated numbers. Since these > numbers must be as "chaotic" as possible, I'm using srandomdev(). My problem > is that I'm only able to compile my software on *BSD and certain distros of > Linux seem to be stripped of the call. This forces me to rely on > srandom(time(NULL)) for portability. > > I would like to know how "random" (that is, how inprobable a pattern will > appear) if I use srandom(time(NULL)) instead of srandomdev(). > > Also, would arc4random() be any better in getting the least pattern creation. 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 other > OSes? Sure, compile a test app in your configure script :-) Kris [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (FreeBSD) iD8DBQFCk9JaWry0BWjoQKURAlPlAKCZU3su3Fo5FRvpkziE5A/mIM/0sQCgjmaX IL8O4VDz97FTTN0R+7NRliM= =tG7b -----END PGP SIGNATURE-----help
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