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#271
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On 21 Dec 2003 23:28:48 -0800, George William Herbert wrote:
Fred J. McCall wrote: (phil hunt) wrote: :On Sun, 21 Dec 2003 23:41:35 GMT, Fred J. McCall ::co-ordination = radio :In which case we're going to KNOW when you're spooling up to shoot and :you'll be dead before everybody gets rolled out and ready. : :Hasve you never heard of encryption, or are you trolling? Hasve [sic] you never heard of traffic analysis, or are you trolling? Done properly, especially with one time pad encryption, one can handle this sort of situation. Consider... the use of CD-R's for pads. They give you 650 megabytes of storage. Assume one message of 1k contents per minute is sent; that works out to a bit over 43 megabytes of pad per month, or about 518 megabytes per year. Each receiving station can have its own pad and its own recipient keying. The messages are sent, every minute, every hour, every day. Most of the time they decrypt to "Nothing is happening, the wind is west at ten kilometers per hour in central Bagwabadad, the temperature is twenty three celsius, our fearless leader (It's generally not a good idea to use canned phrases like this) wishes you good will guarding our important sacred borders, have a nice day. [spaces padding out to 1k total chars]" Or better still, make the null messages just encrypted nonsense. -- "It's easier to find people online who openly support the KKK than people who openly support the RIAA" -- comment on Wikipedia (Email: , but first subtract 275 and reverse the last two letters). |
#272
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On Mon, 22 Dec 2003 08:01:52 -0000, Keith Willshaw wrote:
"Fred J. McCall" wrote in message news ess (phil hunt) wrote: :Usingn the right rogramming tools is important, for example the right lasnguasge or more likely) set of languages. On which lanugages to use, Paul :Graham's essays on language design, and the way Lisp makes it easy :for you to in effect write your own specialised language for the job :in hand, are apposite. Again, this is wonderful until someone has to enhance or maintain the result. EVERY effort written in a 'one-off' special purpose language? Ugh! He wants to use lisp for real time software ! No, he merely thinks Lisp's macro system has advantages, when trying to solve hard problems. -- "It's easier to find people online who openly support the KKK than people who openly support the RIAA" -- comment on Wikipedia (Email: , but first subtract 275 and reverse the last two letters). |
#273
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On Mon, 22 Dec 2003 02:56:36 -0800, Erik Max Francis wrote:
Damo wrote: A civilian is making a cruise missile in his garage in New Zealand for less then 5000 dollars. He has apparently been thwarted by his own government, although his news page isn't terribly clear: http://www.interestingprojects.com/cruisemissile/ Quite frankly, I'm not terribly impressed with his comments; He went to the NZ government before starting the project, told him what he was about to do, and they told him it was legal. Then a few months later, they shut him down by making him bankrupt. -- "It's easier to find people online who openly support the KKK than people who openly support the RIAA" -- comment on Wikipedia (Email: , but first subtract 275 and reverse the last two letters). |
#274
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On 22 Dec 2003 17:41:26 GMT, Bertil Jonell wrote:
In article , phil hunt wrote: On 19 Dec 2003 15:38:09 GMT, Bertil Jonell wrote: In article , phil hunt wrote: I've worked as a programmer for defense contractors (and for other large organisations), and believe me, there is a *lot* of waste and inefficiency. If the software was written right, it could probably be done with several orders of magnitude more efficiency. What competing method is there except for Open Source? Open source -- or rather, using some of the ideas from how OSS projects are btypically run -- is certainly useful. The reason for my question is that I don't think Open Source is very applicable the type of 'sharp edge' military systems you are talking about here. It is very applicable to making programs that help you make sure that every regiment gets the correct number of socks and ammo, but not to making program that handles guidance and target discrimination routines. Especially not if you expect your capabilities to remain anything like secret. Certainly. Using open source software such as operating systems, IP stacks, image processing libraries, encryption libraries and the like would probably be appropriate, and contributing any changes back to those codebases might well be a good idea. The really secret stuff is much less likely to be made available. I also had in mind OSS *techniques*, that is using some of the procedures in infrastructure that OSS projects often used, to do closed-source development. Things like Sourceforge, mailing lists, CVS, packaging as tarballs, etc. -- "It's easier to find people online who openly support the KKK than people who openly support the RIAA" -- comment on Wikipedia (Email: , but first subtract 275 and reverse the last two letters). |
#275
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pervect wrote:
:On Mon, 22 Dec 2003 03:47:23 GMT, Fred J. McCall wrote: : :pervect wrote: : ::From my POV, the key point that I missed in my earlier post (the one ::you just replied to, there have been a bunch since then) is that GPS ::is spread spectrum. : :Which really doesn't buy you much in the way of security. DS-SS :merely makes it easier for the receivers to do ranging functions. : :You're missing the forest for the trees - or maybe you just like to :argue? :-) Or maybe I know more about botany than you do? :I'm going to give a reference of my own: :http://arxiv.org/pdf/gr-qc/9508043 : :for an overview of a more theoretical and high-level approach as to :how GPS works, and to support the following statements I'm going to :make as to how GPS works. I would suggest a pair of alternative documents for more than just a brief relativistic discussion: "NAVSTAR GPS User Equipment Introduction" for an overview of the system and ICD-GPS-200C for a description of what the signals actually look like and how they're used (what you really want to look at are ICD-GPS-203, ICD-GPS-224, and ICD-GPS-225, but those aren't really open to discussion here). :The very basic principles of GPS are that are it is a bunch of rbiting clocks, all of which (in the simplest model) transmit their wn proper time. Right so far. :An observer on the ground, at a fixed location, knows what the proper :time on the satellite must have been when it was sent, when he :recieves the signal, because he knows (or can directly observe) the :satellites orbit. Well, not quite. There's a bit more to it than that. :Therfore, ultimately, an approach based on encryption is going to boil :down to encrypting something that everybody already knows or can :figure out, which is not going to be terribly secure. Except you don't know all of what you need to know, so you really don't know what the clear text is supposed to be. :Spread spectrum tecniques are really crucial to making this system :have the level of security it actually does. Ok, view it that way if you like. I'm really not going to talk about it other than what I've already said. -- "Millions for defense, but not one cent for tribute." -- Charles Pinckney |
#276
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#277
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"phil hunt" wrote in message . .. On Fri, 19 Dec 2003 13:43:49 -0500, Ray Drouillard wrote: Also, since it's not encrypted, it can be spoofed using a local transmitter That doesn't logically follow; it's possible to make non-encrypted data that can't be faked, you just use a digital signature. Is the European answer to GPS going to have digital signatures? If so, how secure are they? Any public-key encryption scheme I have seen uses large prime numbers. They are secure because it's really difficult to factor the product of two large prime numbers. When the Europeans come out with their GPS system, and if it has some kind of a digital signature, wanna make a bet about how long it takes the US military to find a way to spoof it? It might be a long and difficult computer search for the private key, or it might be something as straightforward as using the intelligence community to ahem acquire the codes. Ray Drouillard |
#278
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"pervect" wrote in message ... On Sat, 20 Dec 2003 18:15:56 +0000, ess (phil hunt) wrote: On Fri, 19 Dec 2003 13:43:49 -0500, Ray Drouillard wrote: Also, since it's not encrypted, it can be spoofed using a local transmitter That doesn't logically follow; it's possible to make non-encrypted data that can't be faked, you just use a digital signature. If you don't go to spread-spectrum, your radio links will probably be jammed. (Solution - go to spread spectrum). Spread spectrum signals will be difficult to separate from noise, except at very close range, where the total power level is noticable above the broadband noise. I'd still rate a radio location system using spread spectrum transmitters as rather vulnerable, because the transmitters have to remain in a fixed location for the system to work, and would be prime targets. You don't necessarily need stationary transmitters. After all, the GPS transmitters aren't stationary. If the transmitters transmit their locations to the receivers, the receivers can do the necessary calculations to get a fix. Ray Drouillard |
#279
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"phil hunt" wrote in message . .. On 22 Dec 2003 17:41:26 GMT, Bertil Jonell wrote: In article , phil hunt wrote: On 19 Dec 2003 15:38:09 GMT, Bertil Jonell wrote: In article , phil hunt wrote: I've worked as a programmer for defense contractors (and for other large organisations), and believe me, there is a *lot* of waste and inefficiency. If the software was written right, it could probably be done with several orders of magnitude more efficiency. What competing method is there except for Open Source? Open source -- or rather, using some of the ideas from how OSS projects are btypically run -- is certainly useful. The reason for my question is that I don't think Open Source is very applicable the type of 'sharp edge' military systems you are talking about here. It is very applicable to making programs that help you make sure that every regiment gets the correct number of socks and ammo, but not to making program that handles guidance and target discrimination routines. Especially not if you expect your capabilities to remain anything like secret. Certainly. Using open source software such as operating systems, IP stacks, image processing libraries, encryption libraries and the like would probably be appropriate, and contributing any changes back to those codebases might well be a good idea. The really secret stuff is much less likely to be made available. I also had in mind OSS *techniques*, that is using some of the procedures in infrastructure that OSS projects often used, to do closed-source development. Things like Sourceforge, mailing lists, CVS, packaging as tarballs, etc. Those are mere techniques to facilitate the actual work. And have little to do with actually designing a viable weapons system. The type of paper upon which you compose your missile design has nothing to do with building a missile. And a lot of those OSS techniques are not conducive to weapons design. Folding your mods back into an OSS image processing library, for instance, is not too wise when you are trying to develop a system in secret. Unless of course you want your potential targets to know exactly what your system is looking for (and thereby how to defeat it). Pete |
#280
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"phil hunt" wrote in message . .. On Thu, 18 Dec 2003 22:25:54 +0000, Paul J. Adam wrote: In message , phil hunt writes On Thu, 18 Dec 2003 05:26:01 GMT, Kevin Brooks wrote: That is way beyond even our capabilities. You are talking autonomous combat systems. Yes. The progrsamming for this isn't particularly hard, once you've written software that can identify a vehicle (or other target) in a picture. Falling off a cliff isn't a problem once you've learned how to fly like Superman. Trouble is, that prerequisite is harder than you might expect. Getting a machine to tell a T-72 from a M1A1 from a Leclerc is hard enough in good conditions You don't have to. You have to be able to tell whether it's a vehicle or not, and if it is, is it in an area likely to be occupied by own forces. That 'area' changes hourly. And may not be known until the weapon gets over the target area. : doing so in the presence of camouflage, obscurants and when the crew have run out of internal stowage (so have hung lots of external gear) and maybe stored some spare track plates on the glacis front ('cause they need the spare plates and they might as well be extra armour) gets _really_ tricky. Do you err on the side of "tank-like vehicle, kill!" or "if you're not sure don't attack"? I'd tend to err towards the former. note that it's a lot easy to spot a moving vehicle than a stationary one. Do you waste a missile on a dark green Chevy Suburban, or a tank? Do you have enough missiles for *every* vehicle in front of you? Would it not be embarrasing to have a successful armoured raid broken up by your own missiles? Indeed. Maybe some form of IFF? Even the US/NATO gets that wrong sometimes. Pete |
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