From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266054AbUALELc (ORCPT ); Sun, 11 Jan 2004 23:11:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266055AbUALELc (ORCPT ); Sun, 11 Jan 2004 23:11:32 -0500 Received: from 66-95-121-230.client.dsl.net ([66.95.121.230]:13767 "EHLO mail.lig.net") by vger.kernel.org with ESMTP id S266054AbUALELS (ORCPT ); Sun, 11 Jan 2004 23:11:18 -0500 Message-ID: <40021E47.1070406@lig.net> Date: Sun, 11 Jan 2004 23:10:47 -0500 From: "Stephen D. Williams" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6b) Gecko/20031208 X-Accept-Language: en-us, en MIME-Version: 1.0 To: tabris Cc: "Hunt, Adam" , linux-kernel@vger.kernel.org Subject: Re: High Quality Random sources, was: Re: SecuriKey References: <5117BFF0551DD64884B32EE8CA57D3DB01548A3F@revere.nwpump.com> <4001ECBE.1020009@lig.net> <200401112238.32117.tabris@tabris.net> <200401112247.59418.tabris@tabris.net> In-Reply-To: <200401112247.59418.tabris@tabris.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I was only commenting on the random source, not the rest of the discussion about what a particular keyfob does. Most useful crypto is public-key, i.e. asymmetric encryption, but one-time-pad is a useful fallback since it really is unbreakable if you have a truly random source. OTP absolutely requires that you share the OTP out of band, i.e. you twin a capture of random data. Any transfer makes it as vulnerable as the transfer method. sdw tabris wrote: >-----BEGIN PGP SIGNED MESSAGE----- >Hash: SHA1 > >On Sunday 11 January 2004 10:38 pm, tabris wrote: > > >>On Sunday 11 January 2004 7:39 pm, Stephen D. Williams wrote: >> >> >>>Impossible? I think not. Some "mechanical" devices do exhibit true >>>random capability, especially when enhanced by algorithmic means. >>>To wit: http://www.lavarand.org/ >>> >>>Let me know if you can prove their methods don't provide a true "high >>>quality" random source. >>> >>>I'd like to see their code as a module with an automatic test to make >>>sure that the random source is high quality. In this case, that >>>would mean making sure that the cap was not off the camera. >>> >>> Or, at least if it was that it was pointing at a Lava Lamp! >>>sdw >>> >>> >> just because it passes tests of entropy and probability doesn't make >>it random. it just gets really really close. [hence pseudo-random] >>Everybody knows that /dev/random isn't truly random (it's still a state >>machine, dependent on a hash algorithm [chosen b/c they can take a >>non-random source and make it 'LOOK' random], and you feed it with data >>that is not totally predictable. BUT, there are still enough ways to >>exploit it if you can control/influence the input). it just can pass >>enough tests so that it can be used. >> >> >tere are devices such as this that I admit to not knowing of until now... > > >> and that still doesn't answer the question of how one would use [such >>a device] to 'generate a one time pad'. a one time pad must be >>possessed by both parties that are communicating. and if you have a >>secure channel to transmit an OTP, then you have one that can carry a >>message as well (most commonly, an OTP is used with a time delay. there >>is a single time when a secure channel is available. one [or both] of >>the parties brings it with him/her when he/she travels. >> >> so i'd believe that mebbe this Securikey could hold one... but, any >>USB key-fob type device can. >> >> >Perhaps I should make an amendment. you could perhaps put a geiger counter >and cobalt or other radioactive source into a key fob... but i don't >think it would ever be considered 'safe' to carry. > >other sources may be available as well (i admit to not getting the time to >read the website until just now). doesn't look like it fits in a USB >key-fob yet tho. > > >> I'm sure that someone else can be more knowledgeable on this than I, >>but the general theory holds fast. >> >> > >- -- >If it's worth doing, it's worth doing for money. >-----BEGIN PGP SIGNATURE----- >Version: GnuPG v1.2.3 (GNU/Linux) > >iD8DBQFAAhju1U5ZaPMbKQcRAtDvAJoD1Jm/u3PlJ4EnUQXrPeUjLq14pQCfct9j >1zyYmroBRfkW37/ErNREEx8= >=UrEJ >-----END PGP SIGNATURE----- > >- >To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >the body of a message to majordomo@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html >Please read the FAQ at http://www.tux.org/lkml/ > >