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Date: Fri, 14 Sep 2012 20:50:32 +0100
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From: Ben Laurie <benl@freebsd.org>
To: Mark Murray <markm@freebsd.org>
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Cc: Arthur Mesh <arthurmesh@gmail.com>,
	Ian Lepore <freebsd@damnhippie.dyndns.org>,
	Doug Barton <dougb@freebsd.org>, freebsd-security@freebsd.org,
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Subject: Re: svn commit: r239569 - head/etc/rc.d
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On Fri, Sep 14, 2012 at 8:22 PM, Mark Murray <markm@freebsd.org> wrote:
> Ben Laurie writes:
>> > What??! Have you seen how Yarrow does its harvesting??
>>
>> If you XOR into the as-yet-unharvested buffer, then appropriately
>> aligned repeated input makes the buffer zero.
>

I have no idea what point you're trying to make.

> There is an "if"

"if you use your proposed solution"

> and an "appropriately" in there.

And the input happens to line up.

> The entropy is
> estimated as Zero anyway, in spite of getting "free" TSC jitter, and if
> this is an attack, the system is screwed to begin with.

What I am trying to do is extract whatever entropy there is in the
input. You appear to be saying that there's no point adding extra
entropy because it is estimated at zero. This makes no sense to me.