From owner-freebsd-arch Sat Jul 22 20:18:40 2000 Delivered-To: freebsd-arch@freebsd.org Received: from freefall.freebsd.org (freefall.FreeBSD.ORG [204.216.27.21]) by hub.freebsd.org (Postfix) with ESMTP id 77CBE37B521; Sat, 22 Jul 2000 20:18:38 -0700 (PDT) (envelope-from kris@FreeBSD.org) Received: from localhost (kris@localhost) by freefall.freebsd.org (8.9.3/8.9.2) with ESMTP id UAA55588; Sat, 22 Jul 2000 20:18:38 -0700 (PDT) (envelope-from kris@FreeBSD.org) X-Authentication-Warning: freefall.freebsd.org: kris owned process doing -bs Date: Sat, 22 Jul 2000 20:18:37 -0700 (PDT) From: Kris Kennaway To: "Jeroen C. van Gelderen" Cc: arch@freebsd.org Subject: Re: Quantifying entropy In-Reply-To: <397A5DC9.91DAAD8C@vangelderen.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sat, 22 Jul 2000, Jeroen C. van Gelderen wrote: > Could you make a couple of megabytes of you raw samples > available? I don't have a soundcard at hand but I do > have the FIPS-140 tests and a bunch of others. Sure, they're at physics.usc.edu/~kennaway/soundnoise.bz2 (just over 10M worth) Some interesting numbers: The shannon entropy of this sample as a pure probability distribution is 8.50 bits/sample (they're 16-bit signed values). Compressing with gzip -9 and comparing the file sizes gives an entropy estimate of 10.4 bits/sample. Compressing with bzip2 -9 gives an estimate of 7.90 bits/sample, suggesting there is indeed some time-correlation in the signal noise. Kris -- In God we Trust -- all others must submit an X.509 certificate. -- Charles Forsythe To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message