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Date:      Wed, 19 Jul 2000 11:46:01 -0600
From:      Warner Losh <imp@village.org>
To:        Peter Dufault <dufault@hda.com>
Cc:        current@FreeBSD.ORG
Subject:   Re: randomdev entropy gathering is really weak 
Message-ID:  <200007191746.LAA82887@harmony.village.org>
In-Reply-To: Your message of "Wed, 19 Jul 2000 09:08:36 EDT." <200007191308.JAA98111@hda.hda.com> 
References:  <200007191308.JAA98111@hda.hda.com>  

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In message <200007191308.JAA98111@hda.hda.com> Peter Dufault writes:
: > The reason why ntp is interesting is that we compare the received data
: > with our unpredictable local clock.  It is the result of this comparison
: > which is good entropy bits.
: 
: Is the resolution of thermal sensors on many new motherboards and
: CPU high enough to get thermal randomness?

Yes.  You'll also find that the voltage drifts as well.  However, I
doubt you'd be able to get more than 1 bit out of the voltage
readings.  The thermal readings, depending on their precision, would
also yield several random bits.  But this several may be only 3 or 4.
The temperature varies based on work load and on the climate controls
in place at the site.


Warner


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