From owner-freebsd-arch Sat Jul 22 7:36:28 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 949F137C232; Sat, 22 Jul 2000 07:36:24 -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 QAA00408; Sat, 22 Jul 2000 16:36:14 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: "Louis A. Mamakos" Cc: Brian Fundakowski Feldman , Kris Kennaway , arch@FreeBSD.ORG Subject: Re: Quantifying entropy In-reply-to: Your message of "Sat, 22 Jul 2000 10:32:24 EDT." <200007221432.KAA66024@whizzo.transsys.com> Date: Sat, 22 Jul 2000 16:36:14 +0200 Message-ID: <406.964276574@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message <200007221432.KAA66024@whizzo.transsys.com>, "Louis A. Mamakos" writ es: >I think we're overestimating the extent of the threat. Hell, an attacker >could fire a particle beam at phk's geiger counter and comprise it as well. Actually, he would just give me more random bits that way :-) The way to use a geiger is to time three events: e1 e2 e3 |-T1---|---T2--| if T1 > T2 bit == 0 else if T1 < T2 bit == 1 else try_again; And invert every other bit to remove any systematic bias. -- 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