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Date: Thu, 6 Sep 2012 15:47:03 -0700
From: Arthur Mesh <arthurmesh@gmail.com>
To: RW <rwmaillists@googlemail.com>
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Cc: freebsd-rc@freebsd.org, freebsd-security@freebsd.org,
	Doug Barton <dougb@freebsd.org>
Subject: Re: svn commit: r239569 - head/etc/rc.d
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On Thu, Sep 06, 2012 at 11:01:57PM +0100, RW wrote:
> Reusing a secure entropy file is only a problem if the complete history
> of yarrow, from boot until some significant output, is exactly the same
> as on a previous boot.

Not sure I agree. It's not the only problem. It's the worst problem;
in the situation you describe, you'll end up with identical output from
/dev/random.

> Once something changes you get a completely
> different sequence of yarrow cipher-keys; a counter or writing out
> a new entropy file will both do this, but OTOH so will any difference in
> harvested entropy such a sub-nanosecond difference in timing.

You're correct. Are you arguing that we shouldn't recycle /entropy after
it's used?  If so, why are you okay with making life easier for active
attackers?