December 2003 - cypherpunks-legacy

Re: Nuclear Weapons Material
by shamrock＠netcom.com 17 Dec '03

17 Dec '03

This thread is just too interesting... Mikolaj wrote: > > This also depends on the type of bomb. In a two-stage fusion >bomb, you are quite correct - the tritium-deuterium/tritium fusion >reaction gives the boom. However, in a three-stage bomb, there is an >additional fission reaction, this due to the fact that the neutrons >produced by the fusion reaction have the precise energy required to >fission U-238. Since U-238 is vastly easier to obtain than enriched >U-235, there is no great problem with sticking in half a tonne of it. >Around that you can add cobalt jackets, etc, for more interesting >effects. > What does the cobalt jacket do? -- Lucky Green <shamrock(a)netcom.com> PGP public key by finger

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Re: Something of Interest (fwd)
by nobody＠REPLAY.COM 17 Dec '03

17 Dec '03

Alan wrote: > >>>Is it just me, or does anyone else remember a similar message being pumped > >>>out about the same time Bell was raided (April 1). > I found the actual article. It was forwarded to the list by someone. > (Maybe Igor?) The headers are interesting. I have the full header set if > anyone is interested... > > This post did not seem to get posted to the list, but only as a forward... It is my recollection that Igor filters the incoming files that use a blind cc: to cypherpunks(a)(anylist).com and checks to see if they are spam with cc:'s to a thousand email addresses or are meant for the cypherpunks list in specific. If they are not just random spam, then Igor forwards them to the list subscribers, which accounts for the headers showing the post as a forward rather than as sent directly to the list.

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Are RSA licenses fungible?
by paul＠poboy.b17c.ingr.com 17 Dec '03

17 Dec '03

-----BEGIN PGP SIGNED MESSAGE----- I'm developing some software for use in psychiatric research; basically, about 20 field sites will run the software, collect data, and modem it back to a mothership central site. The encryption & security needs are evident, and one of the main reasons to meet these needs is that the doctors involved perceive that they might be liable for leaks. Code based on Pr0duct Cypher's PGP Tools would do exactly what I want done The good doctors' general fear of liability means that I can't expose them to the risk of unlicensed use of RSA's patents (even though I think those patents are questionable, my job is to not get my clients involved with that question.) So.. if I buy 20 licenses of ViaCrypt PGP, then proceed to use PGP 2.6-based code in my applications, does that constitute a legitimate solution? - -Paul - -- Paul Robichaux, KD4JZG | Demand that your elected reps support the perobich(a)ingr.com | Constitution, the whole Constitution, and Not speaking for Intergraph. | nothing but the Constitution. -----BEGIN PGP SIGNATURE----- Version: 2.6 iQCVAgUBLlyusKfb4pLe9tolAQHH6gP/cA/UwqpKqIDXv4ztBkUzyvLPypOUWRYB OoYGcE/AZF7vO1fgvkObZgwP59QC1Z0fsVU+lNUVgW8qIfadcwb0awBHcooQZ3OL 4d4cX9oD0ARxOrFoA4lFBU97k3lBXa+szyBD+hN2qyIxXUvHPPn5SZcZGYb7swMf zHfDONdqnq8= =FwPl -----END PGP SIGNATURE-----

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Re: U & Pu "poisoning of the environment"
by jdd＠aiki.demon.co.uk 17 Dec '03

17 Dec '03

> >One doesnot need to detonate the Uranium/Plutonium one can poison the > >watersuplies and make havoc with The Simple Bear Necessities of life. > > Well, I wouldn't want to snort the stuff daily, but its toxicity > has been overrated in the popular press. > > Epidemiologic studies of workers [even wartime workers with impressive > body burdens/ exposures] in a number of uranium bomb-making centers have > found ~ no health effects. This is quite similar to saying that nerve gas is harmless because scarcely anyone working in storage areas has been killed by it. Or that bullets won't harm you because people handle crates of them and they don't get shot. -- Jim Dixon

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Is pay-per authentication possible absent trust?
by Jason W Solinsky 17 Dec '03

17 Dec '03

I'm having a problem patching up a serious hole in one of my protocols and I was wondering if anybody here had a solution. [Actually I suspect that the hole is impossible to patch, but I haven't been able to convince myself of that yet so intuitive "proofs" would also be appreciated] Here is the situation. Charles runs a certification agency. He might be certifying that you have some basic competency so that people will hire you. Or he might be certifying that you buy lots of computers with big brother inside microprocessors, thus making advertisers who want to sell software for big brother inside computers [i.e. Microsquish] willing to pay extra money for your time. Either way, Charles's certification is worth money to you. But the value to you isn't a constant amount. Each time you use the certification, you derive additional value from it. So Charles figures that it makes much more sense to sell his certifications on a per use basis... People who only occasionally need the certification will be able to afford it and Charles can gouge people who need the certification frequently for all they are worth. To do this Charles adopts a protocol in which his signatures are time dependent. Everybody can verify that his signatures a valid for the time at which a signature is required, but only Charles can figure out what the correct signature is for time T in polynomial time. [Note: There are many alternative methods of accomplishing this, but they all seemed to have the same hole... If you can find a way to patch the hole that requires changing this protocol it would still solve my problem]. So Charles sells you one-time certifications, and Microsquish pays you extra for those certifications and everybody is happy. Then, one day, Microsquish decides that Charle's certifications aren't worth as much as they used to be, so it lowers its price (for your time) to slightly greater than what Charles is charging you. Well this makes you unhappy so you complain to Charles, but he refuses to change his price. This makes you angry at Charles and causes you to wonder if there isn't a way to lower your certification costs. Enter Ingve the insurance salesman. Ingve will guarantee to others that you are certified by Charles by offering them bets. So suppose that Microsquish sends you its advertising agent and the agent is offering a 10 nano-slinkys [a cyberspatial monetary unit] bonus if you can produce one of Charles's certifications. Charles is charging 8 nano-slinkys. In steps Ingve. You've told Ingve that you are certified by Charles as a frequent purchaser of big brother inside computers. So Ingve says: "I'll convince Microsquish to accept my word that you have Charles's certification in exchange for just four nanoslinkys. But if at my request you ask for the certification and Charles's says you aren't certified then you owe me 64 nano-slinkys." Since you are sure that you are certified you accept the deal. Then Ingve goes to Microsquish and offers to insure your certification. Each time Microsquish accepts a certification from Ingve for you, Ingve will pay Microsquish 2 nano-slinkys but will be able to get your business (and thus offset that with the four nano-slinkys). But, if it turns whenever Microsquish wants to it can check up on your certification from Charles at cost (8 nano-slinkys). If Charles certifies you all is well. Otherwise, you owe Ingve 64 nano-slinkys and Ingve has to pay up Microsquish's insurance claim (which could be quite large depending on the policy. The result of all this is that Charles is cheated out of his revenue. Ingve, You and Microsquish profit, but Charles fails to reap the benefits of his certification. The question is: Is there a secure method that charles can use to prevent the "Ingve the insurance salesman attack"? Cheers, Jason W. Solinsky

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Re: Nuclear Weapons Material
by David K. Merriman 17 Dec '03

17 Dec '03

> > >I wonder why the issue of bomb parts is now being given such a >huge push in the press? > Because the last Crisis of the Week is running out of steam (viewer interest) - not that I'm cynical or anything. :-( Dave Merriman - - - - - - - - - - - - - - - - - - - - - - - - - - Finger merriman(a)metronet.com for PGP/RIPEM public keys and fingerprints. Unencrypted Email may be ignored without notice to sender. PGP preferred. Remember: It is not enough to _obey_ Big Brother; you must also learn to *love* Big Brother.

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U & Pu "poisoning of the environment"
by pstemari＠bismark.cbis.com 17 Dec '03

17 Dec '03

> In all of these cases there is a serious attempt to make sure that the > workers are not harmed by the dangerous substances involved. I must > say that the phrase "impressive body burdens" is fairly incomprehensible. "Body burden" refers to the amount of Pu that has been ingested and remains in the body. The entire point of safeguards is to minimize body burden and exposure. If someone has a "impressive body burden", it means the safeguards didn't work.

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Re: Nuclear Weapons Material
by cfrye＠mason1.gmu.edu 17 Dec '03

17 Dec '03

One of the secrets the government didn't want out was the nature of the gamma ray trigger, as the concept of explosively compressing U235 was *relatively* widely known (this is pre-1980). Curt

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Re: Using PGP on Insecure Machines
by p.v.mcmahon.rea0803＠oasis.icl.co.uk 17 Dec '03

17 Dec '03

James Hightower writes: > Which brings me to the question; "What ARE people using, and what are > they GOING to use?" Can anyone point me to a survey of the most used > Consumer will be using so that we can be there with strong, usable ^^^^^^^^ Who? > crypto when he gets there. ^^^^^ Where? Or less tersely, which users of messaging are you interested in providing crypto for? Apart from the Defence sector, there seem to be three main communities: 1 "Formal" inter-business electronic messaging using commercial value-added networks (VANs) - which are perceived as secure - and associated user agent software (which varies greatly). About fifty thousand North American companies are "there" already (for EDI, and at a cost). Leakage (due to high VAN costs) of formal messaging business from VANs onto the insecure Internet is not yet significant - although CommerceNet will doubtless fix that. 2 Intra-organisation nessaging based on LAN or corporate workflow and email systems. This has built both bottom-up and downwards (e.g. from PROFS or equivalent). The prevalent software is diverse, proprietary and volume. I don't have total market figures to hand, but as an example, the 11JUL94 Government Computer News ranks MS Mail (Windows 3), cc:Mail (Windows), cc:Mail(DOS), MS Mail (PC Networks), and WordPerfect Office as the most preferred e-mail packages amongst Federal users. I would expect a similar list in most commercial email-enabled organisations (with the addition of Lotus Notes). Varying security facilities are bundled within these packages already. 3 The "informal messaging" sector (including most Internet traffic). The associated software is more diverse and "open", but its users have a marginal and/or occasional need for end-to-end / message-transfer security. Note: for both 1 and 2, an "insecure machine" (i.e.: with administrative intrusion potential into an individual's messaging security) is more likely a requirement than a problem for medium/large corporations - as management supervision and control over information assets need to be possible. -- Tim May writes: > I had assumed the poll was of *us*, which is both a manageable poll to > take, and a useful one. What would be done with the results? --- James A. Donald says: > High Tech industry has considerable experience with surveys of > consumers for nonexistent products. > > Such surveys are useless at best, and dangerous at worst. On the other hand, how else do you find out whether a sufficiently serious market exists to warrant investment in developing / productising a technology ? - pvm

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Digested Version no longer available
by Robert A. Hayden 17 Dec '03

17 Dec '03

It is with deep regret that I inform you all that the digested version of the list is no longer available. The machine that the digested version was running from was removed from the network due to a power-ploy by faculty and administration in computer services and the computer science department. It is my hope that in about two weeks when school officially resumes, I will be able to get the machine restored. At that point, I will attempt to recoordinate with Eric to get the digested list set back up. I apologize. ____ Robert A. Hayden <=> hayden(a)krypton.mankato.msus.edu \ /__ -=-=-=-=- <=> -=-=-=-=- \/ / Finger for Geek Code Info <=> I do not necessarily speak for the \/ Finger for PGP Public Key <=> City of Mankato or anyone else

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Re: Nuclear Weapons Material
by koontzd＠lrcs.loral.com 17 Dec '03

17 Dec '03

>The ammo used by the A-10 chain gun uses a depleted uranium core that is >designed to defeat Chobam and other types of reactive armor. It is also >used in F-14, F-15, F-16, and F-18's that are tasked with ground attack >missions where active armor tanks are expected to be encountered. A clarification. The A-10 is equipped with a 30mm weapon, the fighters are equipped with 20 mm. Its the size (30mm) along with the density (depleted uranium) that makes the kinetic weapon so effective against armored targets.

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Re: Nuclear Weapons Material
by jdd＠aiki.demon.co.uk 17 Dec '03

17 Dec '03

In message <199408251440.HAA06649(a)netcom7.netcom.com> Mike Duvos writes: > > I wonder why the issue of bomb parts is now being given such a > huge push in the press? Maybe because several people have been arrested in Germany and Russia over the last week or two. According to the UK press a group at a Russian nuclear weapons facility were stealing tens of kilos of the stuff, and one guy supposedly was willing to trade a kilo of plutonium for 70 bottles of vodka. Occasionally coverage in the press does reflect events in the real world. -- Jim Dixon

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Re: U & Pu "poisoning of the environment"
by jdd＠aiki.demon.co.uk 17 Dec '03

17 Dec '03

In message <9408251512.AA11369(a)focis.sda.cbis.COM> "Paul J. Ste. Marie" writes: > > > Epidemiologic studies of workers [even wartime workers with impressive > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > body burdens/ exposures] in a number of uranium bomb-making centers have > ^^^^^^^^^^^^^^^^^^^^^^^^ > > > found ~ no health effects. > > > > This is quite similar to saying that nerve gas is harmless because > > scarcely anyone working in storage areas has been killed by it. Or > > that bullets won't harm you because people handle crates of them and > > they don't get shot. > > No, it is not. If you had read the message more carefully, you would > have had to phrase your example as, "This is quite similar to saying > that nerve gas is harmless because scarcely anyone who has inhaled > substantial amounts of it has been killed by it." In all of these cases there is a serious attempt to make sure that the workers are not harmed by the dangerous substances involved. I must say that the phrase "impressive body burdens" is fairly incomprehensible. But nevertheless, my point stands: workers are carefully protected from the plutonium and U235 in nuclear weapons plants. When their radiation badges show what is considered a high level dose, this does not mean that they have been exposed to anything like, say, the radiation from a kilo of unshielded plutonium. If radioactive substances are used as weapons, the intention will be to do the maximum possible damage. I don't think that anyone would survive for long after exposure to, say, a suspension of plutonium in air designed to be breathed in, perhaps as an aerosol. To repeat my point: you say that statistical studies of workers in nuclear weapons plants which are specifically designed to minimize the effects of radiation show that radiation has done little harm. Well, I should hope so. On the other hand I say that such studies are poor criteria for judging the effects of radiation intended to do the maximum possible harm. I think that this is really indisputable. -- Jim Dixon

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Re: Nuclear Weapons Material
by jdd＠aiki.demon.co.uk 17 Dec '03

17 Dec '03

In message <199408251633.JAA16087(a)netcom4.netcom.com> Mike Duvos writes: > Uranium is not particularly radioactive, being a long lived alpha > emitter. This is true of plutonium and some other fissionable > materials as well. I can handle clad uranium or plutonium > reactor or bomb components in complete safety with no protective > clothing needed. The only hazard is from ingestion of the > material, or from accumulation of decay products such as radon in > a badly ventilated area. > > Workers in nuclear fuel fabrication facilities have been known to > use small disks of plutonium sintered into a ceramic base as > poker chips. Is this true? I mean, do you know it from personal experience? I was told by what I considered to be reliable sources that plutonium was extremely toxic. Upon reflection, I am sure that this is the word that was used: toxic, not radioactive. By "clad", do you mean coated in lead? -- Jim Dixon

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swIPe
by alex 17 Dec '03

17 Dec '03

The other day, while I was poking around the C'Punk FTP site, I ran across swIPe, the low-level network security protocol by Matt Blaze and John Ioannidis. I'm not as knowledgeble as many of the people here, but swIPe strikes me as "The Right Way" to apply crypto to net-communications. Instead of having secure email, secure mosaic, secure telnet, etc., you have secure IP traffic. It's comparatively simple, it's very flexible, and it's transparent. I haven't heard much about swIPe, and I was wondering if someone could bring me up to speed on it, let me know the status of the project, the conventional wisdom, etc. In particular, I'd like to know if anyone uses swIPe with Linux. Also, I'm curious about the practicality of using swIPe as a component in a larger secure mail (or secure anything) system. If I understand the situation properly, swIPe would only be one piece of a total security system. You'd still need to protect against unauthorized break-ins on your machine, and you'd still have to trust root, you'd still depend on the OS's built-in security, you'd still need a CFS type of program to store your swIPe keys, etc. Finally (I know I'm asking a lot of questions here), does anyone have any pointers to anything about the key-exchange system (apart from what was at soda)? Thanks, Alex

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Re: Nuclear Weapons Material
by jdd＠aiki.demon.co.uk 17 Dec '03

17 Dec '03

In message <9408251708.AA04970(a)vail.tivoli.com> Mike McNally writes: > Mike Duvos writes: > > The idea is that the > > uranium penetrates the armor and the charge then explodes once > > the round is inside. > > I don't know much about modern munitions, but I do know that armor > piercing rounds may have no charge in them at all. Most do. RPGs, for example, definitely do. As I recall, a shaped charge punches a tiny hole through the armor and then injects a blob or jet of liquified metal into the vehicle. It's much worse than a ricochet. The explosion occurs outside the tank, driving the jet of metal in. Armor piercing artillery rounds are called HEAT (High Explosive Anti- Tank). The name says it all. -- Jim Dixon

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Re: Nuclear Weapons Material
by jdd＠aiki.demon.co.uk 17 Dec '03

17 Dec '03

In message <199408251812.NAA00474(a)zoom.bga.com> Jim choate writes: > I would like to request some reference on the use of Uranium in the casing > of a shell or round. The casing gets thrown out on the ground (by both > aircraft and tanks) when the round goes off. There is no reason to use > anything other than brass or steel for this. There is some confusion in terminology here. The brass case is indeed discarded when the round is fired. Byt 'casing' he means the exterior of the warhead. The word 'round' is used for both the warhead+gunpowder+brass and then for the warhead itself. Larger artillery pieces do not use a brass shell case at all. The round is loaded, and then the powder is rammed in after it. > I can find no reference any U-core round being HE or otherwise carrying a > charge. In all cases that I am aware of and can find reference to it is simply > a KE attack on the target where the by products of the impact bounce around > inside the target grinding up whatever is in there. I believe that this is true, except that the 'products of the impact' are drops of metal and what they do is worse than grinding something up. -- Jim Dixon

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Re: Nuclear Weapons Material
by dance＠cicero.spc.uchicago.edu 17 Dec '03

17 Dec '03

>I wonder why the issue of bomb parts is now being given such a >huge push in the press? For one thing, Germany has been going ballistic because of the sheer number of people trying to smuggle Uranium/Plutonium from the ex-Soviet Union across its borders for sale on the world market. The Christian Science Monitor had a good article on this last week sometime. _/_/_/ _/_/_/ _/ _/ _/_/_/ _/ _/ Disobedience is the true _/ _/ _/ _/ _/ _/ _/_/ _/ foundation of liberty. _/_/_/ _/ _/ _/ _/ _/_/_/ _/ _/ _/ The obedient must be slaves. _/ _/ _/ _/ _/ _/ _/_/_/_/ _/ _/_/_/ _/_/_/ _/_/_/ _/_/_/ _/ _/ _/_/_/ "Civil Disobedience" _/ (Thoreau)

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'What A Long Strange Trip It's Been' by Lewis Sanders
by ajteel＠andronix.org 17 Dec '03

17 Dec '03

================================================= === "What A Long Strange Trip Its Been: === === A Hippy's History Of The 60's & Beyond" === === By Lewis Sanders, 2nd. Edition, 1994 === ================================================= Dear Friend I am sending this special announcement to all of the addresses of net.friends that I found in my mailbox. I have come across a book that I am sure that many of you may be interested in. This is a one-time, special announcement and is _not_ the start of new mailing list. The book is, in my opinion, important enough to tell all of you about. "What A Long Strange Trip It's Been" is now available in an autographed, limited edition printing. This new and updated version of Sanders' 1989 underground classic has the reviewers raving. Readers can't put it down. Colleges are using it with great success in American History and Sociology classes. With unique first-hand knowledge of the subject, Sanders writes a detailed account of the people and events of the era. Users of my InfoBot might be especially interested in the appendix regarding 'world domination'. To obtain a brief flyer containing excerpts, a synopsis, and reviews about this riveting account of major trends of the last three decades, simply send a message to walstib-info(a)andronix.org. The author may also be reached at walstib(a)andronix.org <Lewis Sanders>. If you are not interested, _please_ _disregard_this_message_. Regards, -A. J.- =*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-= Without Prejudice UCC 1-207, A. J. Teel, Sui Juris, SLE <ajteel(a)andronix.org> USPS: A.C.T., A. Freeman, c/o 637 So. Broadway #B-212, Boulder, NON-DOMESTIC Colorado Republic, (u).S.A., P.Z.: 80303/TDC (303) 687-4935 24 Hours NIC: AJT =*=-=*=-=*=-= Random Liberty/Freedom Quote for this message =-=*=-=*=-=*=-=*= TREATY. "... Treaties usually provide for their own termination, but independently of that it has been held that when a treaty becomes dangerous to the life or incompatible with the independence of a state or a permanent obstacle to the development of its constitution or the rights of its people, it can be abdicated, and also when the condition of affairs which formed the basis of the treaty has become so modified by time that its execution has become contrary to the nature of things and the original intent of the parties: 22 Ct. Cls. 408." --Bouvier's Law Dictionary, 1897 edition. (Is NAFTA a "treaty" or an "agreement"?!) =*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-= No posts from .andronix.org may be commercially quoted without permission. Email frink-info(a)andronix.org for important 'Freedom, Ink.' Archives Data. Email walstib-info(a)andronix.org for What_A_Long_Strange_Trip_It's_Been Info.

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Re: Nuclear Weapons Material
by David K. Merriman 17 Dec '03

17 Dec '03

> >Occasionally coverage in the press does reflect events in the real >world. >-- >Jim Dixon > Christ, don't let the press find out they screwed up like that - otherwise, we'll *never* hear another bit of Real News (tm) again! Dave "I wish I wasn't joking so much" Merriman - - - - - - - - - - - - - - - - - - - - - - - - - - Finger merriman(a)metronet.com for PGP/RIPEM public keys and fingerprints. Unencrypted Email may be ignored without notice to sender. PGP preferred. Remember: It is not enough to _obey_ Big Brother; you must also learn to *love* Big Brother.

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No Subject
by Anonymous 17 Dec '03

17 Dec '03

A couple comments: (1) They are not offering any form of encryption -- seem to feel that the intervening Internet mail spools are secure from would-be blackmailers. (2) Are suicide hotline communications, like psychiatric counseling, privileged communications? In what jurisdictions? ------------------------------ Subject: Support for the Suicidal - Full Launch - jo(a)samaritans.org Press Release August 17, 1994 The Samaritans are a non-religious charity offering emotional support to the suicidal and despairing. A test of "Help By E-mail" launched on July 14, 1994 proved so successful that an Internet domain is now open and is reached by mailing jo(a)samaritans.org. The E-mail service is run from Cheltenham, England, and is reached from anywhere with Internet access. At the launch, Mike Haines, the Director said: "During the test month we received over 200 messages. Many were from well wishers, journalists and academics but there were around 15 very desperate people as well. The need for a full launch of our service with an easier address was amply demonstrated." The Samaritans have been offering support to the suicidal and despairing for over 40 years by phone, visit and letter. Callers are guaranteed absolute confidentiality and retain the right to make their own decisions including the decision to end their life. Samaritans are carefully selected and prepared for this work (for which they are not paid). Those working with E-mail have additional training. Volunteers read and reply to mail every day of the year. A nominal end date of December 31, 1994 has been set but initial results have been so encouraging that it is likely to run indefinitely. The idea of an Internet service was born when a volunteer was exploring the UK based CIX conferencing service. Here, he discovered the "suicidehelp" self help group and Newsnet groups such as "alt.support.depression". After discussions with The Samaritans General Office it was decided to try offering a service from Cheltenham. The kind donation of a modem by US Robotics was a great help as was the assistance of staff at Compulink Information Exchange (CIX). The Samaritans of Cheltenham and District 3 Clarence Road CHELTENHAM Glos England Emergency phone: +44 242 515777 Press enquiries: +44 452 854017 E-mail: jo(a)samaritans.org (samaritans(a)cix.compulink.co.uk retained) Anonymous E-mail: samaritans(a)anon.penet.fi (Extremely Slow!) <end>

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Re: Voluntary Governments?
by wcs＠anchor.ho.att.com 17 Dec '03

17 Dec '03

> > Here, someone will surely object that by this definition, the Mafia can > > be considered a government. > > Well, yes, of course. It has quasi-governmental functions in southern > Italy. ... and in Central New Jersey and parts of upstate New York as well :-)

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Re: Nuclear Weapons Material
by mpd＠netcom.com 17 Dec '03

17 Dec '03

Jim Dixon <jdd(a)aiki.demon.co.uk> writes: > I was told by what I considered to be reliable sources that > plutonium was extremely toxic. Upon reflection, I am sure > that this is the word that was used: toxic, not radioactive. Plutonium-239 emits alpha particles, which are helium nuclei, at an energy of approximately 5 MeV. Such particles are bulky and can be stopped by a few centimeters of air, or a thin piece of paper or metal foil. In order to cause damage, alpha emitters like plutonium must come in intimate contact with a material, such as the tissues of your lungs or bones or the inside of your favorite memory chip. A billionth of a gram of plutonium inhaled or swallowed is something to seriously worry about, but you can hold a lump of the stuff in your hand as long as it is covered with a leakproof cladding or vitrified into a ceramic. It is in this sense that plutonium is extremely toxic and hazardous to the environment, while at the same time not being particularly radioactive. Heavy shielding is not required between you and it. Of course once fissionable fuels are irradiated, they become extremely radioactive due to a wide spectrum of short-lived fission byproducts and then require precautions when they are handled. > By "clad", do you mean coated in lead? No - the desired properties of cladding are resistance to corrosion and heat, as well as a low absorption cross section for thermal neutrons. We're talking about materials like zirconium and iridium here, as well as specialized alloys of stainless steel. -- Mike Duvos $ PGP 2.6 Public Key available $ mpd(a)netcom.com $ via Finger. $

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$10M breaks MD5 in 24 days
by Hal 17 Dec '03

17 Dec '03

I am not attending the Crypto conference, but I sat in on the evening "rump session" the other day. One of the more interesting papers had a claim (with little detail, unfortunately) that for ten million dollars you could build a machine that would "break" MD5, in the sense of finding another message which would hash to the same as a chosen one, in 24 days. This result did not depend on any internal structure in MD5, but was purely a result of the hash size (128 bits) and the time it takes to calculate a hash. The main new result which allowed this was a more efficient way of handling a parallel search for collisions (two messages which hash to the same thing). In some earlier methods, n machines provide only a sqrt(n) speedup. The new method improves this, although my notes don't show exactly how close they come to an n-fold speedup. The Secure Hash Standard (SHS, aka SHA) is, they said, 64K times slower, hence this technique would take 64K times longer (or cost ~64K times more?) to break that hash. I don't think this is probably anything to really worry about, but maybe it points out a need for a longer hash in the next few years. Hal P.S. The paper was by Paul C. van Oorschot & Michael J. Wiener.

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No Subject
by Anonymous 17 Dec '03

17 Dec '03

Kudos to Hal Finney for his descriptions of Stefan Brand's offline cash. As with other offline cash protocols it contains the following assumption: > Let's call the user Irving, and > the number which encodes his identity (it might just be his bank account > number in this case) we will call I. What happens when we've caught Irving double spending (or million spending?) Is it guaranteed that Irving will have enough in his bank account to cover the fraud? I don't see any way to guarantee that except for absurdly large security deposits. Also, are bank accounts required to be in True Names so that multi spenders can be caught and punished? If so, how do we prevent the use of numbered accounts, Duncan Frissel's nom de guerre accounts, etc. and do we really want to set up that kind of True Name infrastructure? Also, what about stolen coins? If Irving can succeed in stealing a coin from Jane without her knowledge, Irving can spend it untraceably as many times as he can get away with (perhaps thousands or even millions, depending on what security precautions we layer above the offline cash), and Jane gets fingered. On the other hand, Jane might simply give Irving some coins, plausibly claim they were stolen, and split the proceeds from Irving's spending spree. In general, multi spending might occur because of accident, malice, or a combination of those two factors. How do we distinguish between accident and malice to determine liability, reputation loss and/or punishment?

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