Date: Tue, 18 Jul 2000 08:05:51 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Mark Murray <mark@grondar.za> Cc: "Louis A. Mamakos" <louie@TransSys.COM>, current@FreeBSD.ORG Subject: Re: randomdev entropy gathering is really weak Message-ID: <7083.963900351@critter.freebsd.dk> In-Reply-To: Your message of "Tue, 18 Jul 2000 08:04:37 %2B0200." <200007180604.IAA03329@grimreaper.grondar.za>
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In message <200007180604.IAA03329@grimreaper.grondar.za>, Mark Murray writes: >> Actually, you could really use this in ntpd(8), rather than just ntpdate. >> You could crank in the offset and delay samples for each packet >> received from an NTP peer; this will have the effect of adding into >> the entropy pool the "noise" in the latency of the path between you >> and each of your NTP peers. This varies over time with each sample, >> and in fact, NTP goes to considerable effort in it's sample filtering >> to exclude the noisy samples. We need to get that date before it's >> discarded and contribute it to the entropy cause. > >You forget; a snooper watching your (ether)net has access to nearly >all of this information. No, he doesn't have access to the offset from the machines local clock. I ran a quick & dirty test here on some logfiles: that offset is very close to white noise. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD coreteam member | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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