From owner-freebsd-current Mon Jul 17 23: 6: 9 2000 Delivered-To: freebsd-current@freebsd.org Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.40.131]) by hub.freebsd.org (Postfix) with ESMTP id 5AA7C37BA95 for ; Mon, 17 Jul 2000 23:06:03 -0700 (PDT) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.9.3/8.9.3) with ESMTP id IAA07085; Tue, 18 Jul 2000 08:05:51 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Mark Murray Cc: "Louis A. Mamakos" , current@FreeBSD.ORG Subject: Re: randomdev entropy gathering is really weak In-reply-to: Your message of "Tue, 18 Jul 2000 08:04:37 +0200." <200007180604.IAA03329@grimreaper.grondar.za> Date: Tue, 18 Jul 2000 08:05:51 +0200 Message-ID: <7083.963900351@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG 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