Spread-spectrum net (vulnerability of)
You can put up such a network, but given that your boxes have to receive the signal, it will be detectable (but not understandable) to 3rd parties. Anyone who wants to take you down will only need (1) a detector that can point out your boxes and (2) a small caliber rifle. Since the cost to find and destroy is much less than the cost to make and deploy, a covert network of this sort wouldn't last long. An _overt_ network, perhaps a commercial entity that networks an entire city, would be an interesting prospect. The techniques for maintaining location information on actual machines connected to the net, and for updating them as they move, are actually quite simple and well understood (cellular telephones are a simple, dumb version of the technology). The trick is to find out a way that the network can know where you are but not give that information out (even to the owners of the network), without unacceptable overheads.
You can put up such a network, but given that your boxes have to receive the signal, it will be detectable (but not understandable) to 3rd parties.
Not necessarily. Done right, direct sequence spread spectrum transmissions cannot feasibly be detected except by a receiver using the right code. To be sure, ``feasibility'' here is being used in a weaker sense that cryptologists are accustomed to, but the effect is similar. Here are selected passages from "Modern Communications and Spread Spectrum" by George R. Cooper and Clare D. McGillem (McGraw-Hill, 1986) pp 309--311: ...another objective in using spread-spectrum techniques is to make it more difficult for an unauthorized observer to detect the presence of the signal.... When an unknown spread-spectrum signal is to be detected, it is necessary to assume something about what is known. In particular it is assumed that the spread-spectrum code is not known, and that it is desired only to determine the existence of the spread-spectrum signal and not to decode it. This implies then that some form of noncoherent detection must be employed and that the existence of a spread-spectrum signal can be determined only by noting a change in energy between the signal present and the signal not present. Thus it is necessary to consider an energy detector. ... [Engineering mathematics omitted.] ...However, in the case of noncoherent detection, the detectability depends upon the square of [a specific signal-to-noise ratio that they define], rather than upon the first power; thus operating with small values of E/N_0 makes things more difficult for the interceptor than it does for the desired signal receiver.
Anyone who wants to take you down will only need (1) a detector that can point out your boxes and (2) a small caliber rifle.
First he may need (0) the spread-spectrum code. These can be made strong, in a sense similar cryptographically strong random number generators.
Since the cost to find and destroy is much less than the cost to make and deploy, a covert network of this sort wouldn't last long.
This cost comparison might be reversed by forcing the adversary to use incoherent detection. John E. Kreznar | Relations among people to be by jkreznar@ininx.com | mutual consent, or not at all.
You can put up such a network, but given that your boxes have to receive the signal, it will be detectable (but not understandable) to 3rd parties.
That is why we try to make them as cheaply as possible. Then if they are hard to get hold of (hidden/camouflaged/stuck up cliffs and flagpoles) the cost to retrieve them will be prohibitively high.
Anyone who wants to take you down will only need (1) a detector that can point out your boxes and (2) a small caliber rifle.
Errrrr. Hadn't thought of that. Placement will be a major factor, I beleieve.
Since the cost to find and destroy is much less than the cost to make and deploy, a covert network of this sort wouldn't last long. An _overt_ network, perhaps a commercial entity that networks an entire city, would be an interesting prospect.
Depends how you place them. If you put them _on top_ of things, you'd need a helicopter to shoot 'em.
The techniques for maintaining location information on actual machines connected to the net, and for updating them as they move, are actually quite simple and well understood (cellular telephones are a simple, dumb version of the technology). The trick is to find out a way that the network can know where you are but not give that information out (even to the owners of the network), without unacceptable overheads.
This is true. But if we make the things in thick boxes (well, slightly bullet-proof, anyway), and put them in places where theyare hard to shoot at, then we should be right. We would only need a few each suburb. Dwayne.
Anyone who wants to take you down will only need (1) a detector that can point out your boxes and (2) a small caliber rifle.
Errrrr. Hadn't thought of that. Placement will be a major factor, I beleieve.
Since the cost to find and destroy is much less than the cost to make and deploy, a covert network of this sort wouldn't last long. An _overt_ network, perhaps a commercial entity that networks an entire city, would be an interesting prospect.
Depends how you place them. If you put them _on top_ of things, you'd need a helicopter to shoot 'em.
Someone walking around a city shooting a rifle is likely to attract a lot more attention than a secret network would. Secondly, the transmitter doesn't necessarily have to be exposed, it could be kept hidden and only the antenna would need to be exposed. You'd have to be a damn good shot to hit a wire antenna. Plus the antenna would be easy to disguise or hide in many places.
The techniques for maintaining location information on actual machines connected to the net, and for updating them as they move, are actually quite simple and well understood (cellular telephones are a simple, dumb version of the technology). The trick is to find out a way that the network can know where you are but not give that information out (even to the owners of the network), without unacceptable overheads.
This is true. But if we make the things in thick boxes (well, slightly bullet-proof, anyway), and put them in places where theyare hard to shoot at, then we should be right. We would only need a few each suburb.
Well, you may know that you can reach a certain person thru site #127, and that stie #127 can be reached thru site 35 or site 68, and so on...which gives you a sort of virtual-space map, which would reveal nothing about actual phyical location of the sites or the person you are contacting. Suppose you were connected to site #1 and you were communicating with site #3 thru site #2. Site #3 could be 50 meters away, or 2 km, and you would never know the difference because you didn't have any way to directly contact site #3. Hence we have achieved our objective - you know how to contact site #3 in netspace - it has a cybernetic location relative to other sites, but that tells you nothing about it's actual physical location.
Secondly, the transmitter doesn't necessarily have to be exposed, it could be kept hidden and only the antenna would need to be exposed.
Not even the antenna should be visible. Remember, for spread spectrum radio detectable only by the intended receivers (which use the correct spread-spectrum code for coherent detection), the power density should be hardly distinguishable from the ambient noise. One way to arrange this is to put the antenna inside of a physically secure perimeter, outside of which the power density is too low for noncoherent detection. The perimeter can be optically opaque (e.g. a building), as long as it leaks enough r.f. in the direction of the receiver(s) for coherent detection. Preventing noncoherent detection may often require _attenuation_ of an otherwise too-powerful signal, and the building may serve part of this function.
Plus the antenna would be easy to disguise or hide in many places.
Yup. John E. Kreznar | Relations among people to be by jkreznar@ininx.com | mutual consent, or not at all.
participants (4)
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hiscdcj＠lux.latrobe.edu.au -
jkreznar＠ininx.com -
Matthew J Ghio -
Robert J Woodhead