From owner-freebsd-security Mon Sep 4 16:39:40 2000 Delivered-To: freebsd-security@freebsd.org Received: from alcanet.com.au (mail.alcanet.com.au [203.62.196.10]) by hub.freebsd.org (Postfix) with SMTP id 4DBF837B422; Mon, 4 Sep 2000 16:39:34 -0700 (PDT) Received: by border.alcanet.com.au id <115204>; Tue, 5 Sep 2000 10:39:05 +1000 Content-return: prohibited Date: Tue, 05 Sep 2000 10:39:21 +1100 From: Peter Jeremy Subject: Re: yarrow & /dev/random In-reply-to: ; from kris@FreeBSD.ORG on Mon, Sep 04, 2000 at 02:36:30PM -0700 To: Kris Kennaway Cc: Adam Laurie , security@FreeBSD.ORG Mail-followup-to: Kris Kennaway , Adam Laurie , security@FreeBSD.ORG Message-Id: <00Sep5.103905est.115204@border.alcanet.com.au> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-disposition: inline User-Agent: Mutt/1.2.4i References: <39B3992B.7B823DEE@algroup.co.uk> Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On 2000-Sep-04 14:36:30 -0700, Kris Kennaway wrote: >On Mon, 4 Sep 2000, Adam Laurie wrote: >> This is only safe to do if you can guarantee that your sound card is >> protected from outside influence - e.g. radio transmissions putting >> known noise into your data. TEMPEST shielding would be a good start. > >If interference from men in black is part of your threat model ;-) I don't think that follows. For a soundcard to produce useful entropy, you are relying on it's output being primarily thermal noise. Even without deliberate tampering by MIB, the soundcard output can be affected by ambient electrical noise: 50/60Hz line noise and power-supply inverter noise are the most likely culprits in a PC. If you are located close to a radio transmitter, the transmitter can affect the output. Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message