On Wed, 10 Apr 2002, Tim May wrote: >So, if in fact we _are_ talking about each $20 bill having such a >transponder, then why are our arguments about how easy it will be to >shield against remote probing not valid?
Because the economics do not work. People simply aren't knowledgeable/interested enough to actually shield their notes, even if this would only imply buying a foil-shielded wallet. Especially if such wallets are outlawed. (Yes, this is starting to sound like too much, even if governments don't always behave rationally.) >(A stack of bills, or cards, will have extremely poor radiation patterns >from any but the top or bottom bill, and probably their patterns won't >be good either.) How come? True, if a bill is idealized as being planar, you'll have trouble on the plane. Spatial diversity will take care of that. Otherwise, a common note has plenty of surface to do your thing on. Especially at higher frequencies, like UHF and beyond. Sampo Syreeni, aka decoy - mailto:[EMAIL PROTECTED], tel:+358-50-5756111 student/math+cs/helsinki university, http://www.iki.fi/~decoy/front openpgp: 050985C2/025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2
