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From: Mark Murray <mark@grondar.org>
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To: Mike Silbersack <silby@silby.com>
In-Reply-To: Your message of "Fri, 15 Aug 2003 13:41:42 CDT."
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cc: Sam Leffler <sam@errno.com>
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Subject: Re: cvs commit: src/sys/libkern arc4random.c 
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Mike Silbersack writes:
> > How did you validate the this change?  I strongly suggest that mods like
> > this need review before commit.  Subtle problems can go unnoticed for a
> > long time.
> >
> > 	Sam
> 
> I'm fairly confident that I did not add any bugs in this commit.  However,
> I also have no way of knowing if arc4random was working correctly before
> the commit either... How hard would it be to hook up the randomness
> testing code you committed a few months back?  If the testing code is in
> userland, perhaps we could export a /dev/arandom like openbsd does for
> simpler testing.

I have not looked at the locking, but I have looked at this from a
randomness perspective.

With that in mind, I think Mike did the right thing in making sure
that the first chunk of arcfour 'randomness' is ditched after a
rekey. It may be fixing a non-problem, but if there is an undisclosed
problem in determining the arcfour sequence, this helps thwart that.

For the paranoids, this is cheap (almost free), and is solid from a
arcfour-neurotic perspective.

M
--
Mark Murray
iumop ap!sdn w,I idlaH