On Wednesday, April 10, 2002, at 08:23 AM, Michael Motyka wrote: > Or more. > > Not to mention that if you didn't want your money chirping its presence > every time a bad actor pinged it you could just disable the transponder > in the money : > > mechanical pressure or repeated bending > high voltage > high power RF > heat > > For paper money failure rates will probably be high anyway. >
As I said in another article, I think there'll be zero acceptance rate for any _general_ smartcard cash system which: -- has no user-controlled on/off switch, or user authentication (PIN entry at minimum) -- has a wide broadcast pattern -- generally, has a "promiscuous" disclosure model By "general" I mean a store of value to be used roughly as cash and credit cards are used today. Specialized uses such as subway or bridge token systems may have different models. But they will likely also be: -- limited in amount of money -- linked to security protocols, e.g., only BART turnstile nominally has access -- broadcast range and transponder physics tuned to specific use (e.g., BART turnstyle) Now, of course, there may be calls by government for "back doors," for forced promiscuity, but this will complicate the engineering immensely. And shielding is still trivial. I just don't see this as an interesting or fruitful discussion...maybe it's going to be the new version of the "Can I use thermite to destroy my data?" recurring thread. --Tim May "To those who scare peace-loving people with phantoms of lost liberty, my message is this: Your tactics only aid terrorists." --John Ashcroft, U.S. Attorney General
