Re: The future of security
On Sat, 29 May 2004, Russell Nelson wrote: Eugen Leitl writes: If I'm a node in a web of trust (FOAF is a human), prestige will percolate through it completely. That way I can color a whole domain with a nonboolean trust hue, while a domain of fakers will have only very few connections (through compromises, or human mistakes), which will rapidly sealed, once actually used to do something to lower their prestige (I signed the key of a spammer, please kill me now). http://www.web-o-trust.org/ The trouble is that it requires human action, which is expensive and becoming more expensive. The bigger problem is that webs of trust don't work. They're a fine idea, but the fact is that nobody keeps track of the individual trust relationships or who signed a key; few people even bother to find out whether there's a path of signers that leads from them to another person, or whether the path has some reasonably small distance. I have not yet seen an example of reputation favoring one person over another in a web of trust model; it looks like people can't be bothered to keep track of the trust relationships or reputations within the web. Bear - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
Re: Satellite eavesdropping of 802.11b traffic
On May 27, 2004, at 12:35 PM, John Kelsey wrote: Does anyone know whether the low-power nature of wireless LANs protects them from eavesdropping by satellite? Is there some simple reference that would easily let me figure out whether transmitters at a given power are in danger of eavesdropping by satellite? If you assume a perfect vacuum (and note that the athmosphere is fairly opaque at 2.4 Ghz) and perfect antenna's etc - then the specific detectivity needed in space suggests a not unresonably sized (m2's) and cold antenna (below 180k) by very resonably NEP which is commercially available. Given the noise from the earth background (assuming a black body radiator) at 2.4, the Sun and the likelyhood that that largish antenna catches a fair chunk of exactly that then you are at the edge of what would be realistic. However with some clever tricks and processing, like a phase array, you certainly should be able to at least detect that short (1-2mseconds) 100Khz wide 2.4Ghz transmisison at 0.1 watt is happening - assuming you know where to look. Listening in over a country-sized swath over a prologned periods of time is an entirely different story. Given that you then need to be at least 3-4 order's of magnitude better - and that you only get at best square root when increase the easy things like detector size etc, at best - my guess would be that some flying or earthbound is a heck of a lot cheaper and more realistic. There are some good papers on Lidar and Radar detections of clouds in the 3Ghz range at 12km which should give you more of an idea of the spatial resolution you could accomplish. When looking at these - bear in mind that the 2-3kWatt used is reflected by the ice particles - so what gets back is 30-40dBZ less - and that you can use a phased locked loop amplifier easily. Dw - The Cryptography Mailing List Unsubscribe by sending unsubscribe cryptography to [EMAIL PROTECTED]
