From owner-freebsd-arch Sat Jul 22 7:27:16 2000 Delivered-To: freebsd-arch@freebsd.org Received: from critter.freebsd.dk (flutter.freebsd.dk [212.242.40.147]) by hub.freebsd.org (Postfix) with ESMTP id 4C78837B97B; Sat, 22 Jul 2000 07:27:12 -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 QAA00347; Sat, 22 Jul 2000 16:27:04 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Brian Fundakowski Feldman Cc: "Louis A. Mamakos" , Kris Kennaway , arch@FreeBSD.ORG Subject: Re: Quantifying entropy In-reply-to: Your message of "Sat, 22 Jul 2000 10:14:35 EDT." Date: Sat, 22 Jul 2000 16:27:04 +0200 Message-ID: <345.964276024@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message , Brian F undakowski Feldman writes: >> >> Another source of noise could be via the RF tuner in a video capture >> baord. You could get plenty 'o noise on both the audio output as >> well as the noisy video fields when tuned to an unused channel. > >Remember that this approach is easily subverted. An attacker can >compromise your entropy by detecting what frequency you are tuned to >and attack that frequency with predictable data. A protection to >this would be a good implementation of a spread-spectrum and >spectrum-hopping RF tuner, but then you're relying on its PRNG for >the data, really, and if it were that good you'd want to use it anyway ;) Not to be attacking Brian in particular, but I am getting pretty damn tired of seing any suggestion put forth in this thread getting shot down from black helicopters by Elvis. Yes, of course I could simulate the local quardrant of the galaxy at a quantummechanical level and predict everything, but is it really realistic ? The point here is not about making random bits which cannot possibly be compromised. People who need that know how to get that. This is about making the best *realisticly possible* random numbers for FreeBSD (note the emphasis). I can only applaud and congratulate MarkM on what he has managed to do so far in the face of an infinite army of bikeshed building arm-chair generals. -- 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-arch" in the body of the message