From owner-freebsd-current Mon Jul 17 23:25:13 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 E263E37BA4D for ; Mon, 17 Jul 2000 23:25:09 -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 IAA07219; Tue, 18 Jul 2000 08:24:58 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Mark Murray Cc: current@FreeBSD.ORG Subject: Re: randomdev entropy gathering is really weak In-reply-to: Your message of "Tue, 18 Jul 2000 08:17:57 +0200." <200007180617.IAA03375@grimreaper.grondar.za> Date: Tue, 18 Jul 2000 08:24:58 +0200 Message-ID: <7217.963901498@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message <200007180617.IAA03375@grimreaper.grondar.za>, Mark Murray writes: >> People have tried for 30+ years to predict what a quartz xtal >> will do next. Nobody expects any chance of success. Add to this >> the need to predict the difference between one or more NTP servers >> and your local qartz xtal and I think we can safely say "impossible". > >You can't predict this, but you can _measure_ it with a degree of >accuracy. The attacker can use this accuracy to reduce the number >of tries in his attack. No he cannot. The NTP poll period is 64 seconds or longer and unless you have done something special about your hardware, he cannot predict all bits. If he could, ntp would have a longer poll period :-) -- 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