> Tim May[SMTP:[EMAIL PROTECTED]] > > On Tuesday, April 9, 2002, at 10:54 AM, Trei, Peter wrote: > > Putting RF Tags in cash is one of those ideas with Unintended > > Consequences. > > Muggers would love having a way of determining which victims are > > carrying a > > wad, as would many salesmen (and JBTs looking to perform a 'civil > > confiscation' on 'a sum of currency'.) > > Physics-wise, it's a jiveass fantasy. No way are there "micro-strips" > readable from a distance in today's currency, and very likely not in the > next 20 years. (I don't dispute that a careful lab setup could maybe > read a note at a few meters, in a properly-shielded environment, without > any shieding between note and detectors, and with enough time and > tuning. But a wad of bills, folded, stuffed, and with little time to > make the detection...an altogether different kettle of fish.) > Tim: I advise you to get up to speed on this stuff.
I don't recall anyone using the phrase 'micro-strips', which suggests you're erroneously linking this discussion to the theory that there are detectors for the anti-counterfeiting strips built into much modern currency. (FWIW, the old British bills did use a metallic strip - if you scraped off the paper over it you could see the metal. US bills use a polymer strip). We're discussing RFID tags, which are a bit different. In particular, the mu-tag from Hitachi, which is 0.4 mm square, and 60-150 microns thick, depending on version. You can see a picture at http://beta.kpix.com/news/local/2001/12/03/Tiny_Bay_Area_Invention_Could_Cha nge_Security.html (the chips are the things that look like iron filings) There was a good article in the Economist a while back. If you're not a subscriber, it's reprinted (without a registration requirement) at http://www.cfo.com/article/1,5309,5867,00.html A presentation can be found at http://www.hitachi.com/products/electronic/semiconductorcomponent/elecrfid/e lecrfidspecs/index.html The version with the on-chip antenna has a range of about 1cm. The version with an off-chip antenna has a range of 25cm (and possibly up to 1 meter). All it does is spit back a 128 bit number. Most current applications appear to be for checking the authenticity of an item in a cooperative environment. So, yes, at the moment they can't scan your wallet very easily. But this technology is developing as all others are. I don't know about dealing with many similar tags more or less simultaneously, but some of the discussed apps for stock tracking require dealing with this problem. RFIDs are very scary from a privacy point of view, and very little attention is being paid to them. Most are considerably heftier than the mu-chip, but they get cheaper and smaller every year. Mu-chips cost 10-15 cents. > Further, placing the notes in a simple aluminum foil pouch, or a wallet > with equivalent lining, would cut any detectable signals by maybe 30-50 > dB. > Most people don't, and won't do this. You may not worry about the sheeple, but I do. > --Tim May > Peter
