From owner-freebsd-multimedia@FreeBSD.ORG Wed Jun 22 05:21:42 2005 Return-Path: X-Original-To: freebsd-multimedia@freebsd.org Delivered-To: freebsd-multimedia@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id B419C16A41C for ; Wed, 22 Jun 2005 05:21:42 +0000 (GMT) (envelope-from jakemsr@jakemsr.com) Received: from mail231.csoft.net (resin.csoft.net [63.111.22.86]) by mx1.FreeBSD.org (Postfix) with SMTP id 5657243D49 for ; Wed, 22 Jun 2005 05:21:42 +0000 (GMT) (envelope-from jakemsr@jakemsr.com) Received: (qmail 7171 invoked from network); 22 Jun 2005 05:21:44 -0000 Received: from unknown (HELO puff.jakemsr.gom) (63.111.27.87) by mail231.csoft.net with SMTP; 22 Jun 2005 05:21:44 -0000 Received: (from jakemsr@jakemsr.com) by puff.jakemsr.gom (mini_sendmail/1.3.5 16nov2003); Tue, 21 Jun 2005 22:21:41 PDT (sender jakemsr@puff.jakemsr.gom) Date: Tue, 21 Jun 2005 22:21:41 -0700 From: Jacob Meuser To: freebsd-multimedia@freebsd.org Message-ID: <20050622052141.GC23165@puff.jakemsr.gom> Mail-Followup-To: freebsd-multimedia@freebsd.org References: <20050622141220.2cabee63@bofh.spyderweb.com.au> <20050622051314.GB23165@puff.jakemsr.gom> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050622051314.GB23165@puff.jakemsr.gom> User-Agent: Mutt/1.4.2i Subject: Re: tamper proofing audio X-BeenThere: freebsd-multimedia@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Multimedia discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 22 Jun 2005 05:21:42 -0000 On Tue, Jun 21, 2005 at 10:13:14PM -0700, Jacob Meuser wrote: > On Wed, Jun 22, 2005 at 02:12:20PM +0930, Tim Aslat wrote: > > Hi All, > > > > can anyone tell me if it's possible to tamper-proof an audio recording > > in such a way that it can still be played on a normal audio CD player? > > > > I'm not worried about the recording being copied, but I am worried > > about it being modified and want to guard against it. Its for a voice > > recorder project in a lawyers office where they want to be able to > > prove conclusively that a certain audio recording was made on a > > specific machine and hasn't been tampered with. I understand that it > > is impossible to make anything completely tamper-proof, but I would > > like to make it at least difficult for someone to do without some very > > substantial resources and skills available to them. > > Simply verifying the files with checksums (multiple algorithms to > lessen the possibility of "collision attacks") is insufficient? also, bsdav -> http://www.jakemsr.com/bsdav/ (which can be used for audio only) records the system time for every data "frame". may be useful as well. --