Date: Sun, 11 Nov 2001 14:56:12 -0600 (CST) From: Mike Silbersack <silby@silby.com> To: John Kozubik <john@kozubik.com> Cc: <freebsd-hackers@FreeBSD.ORG> Subject: Re: CPU Temp and Fan speed as entropy? Message-ID: <20011111145324.W55153-100000@achilles.silby.com> In-Reply-To: <Pine.BSF.4.21.0111102126430.68269-100000@www.kozubik.com>
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On Sat, 10 Nov 2001, John Kozubik wrote: > > CPU temp and fan speed may or may not be truly random - regardless, I > would be wary of using them as random seeds. First, I suspect that the > range of values is quite small - how much does your temp and fan speed > actually fluctuate over time ? > > Second, I don't have a bios like this in front of me to examine, but I > doubt the granularity is greater than one decimal place. Comments ? > > Due to the small range that these numbers will fall in, I would think the > effectiveness of these values as a random seed are directly related to the > number of places to the right of the decimal these values are measured in. > > ----- > John Kozubik - john@kozubik.com - http://www.kozubik.com I tried running one of the monitoring programs after I sent that message, and found what you guessed above; the accuracy is not early good enough for entropy use. The granularity seems to be about 4 degrees, and the temperature seems to just bounce between two values once every few seconds or so. Oh well. Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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