At 09:48 PM 12/10/01 -0600, Jim Choate wrote:
On Tue, 11 Dec 2001, Anonymous wrote:
To rip the coin, the passenger gives the taxi driver t = s^e1, along with x. The driver can verify that t^e2 = s^(e1*e2) = s^e1 = x mod n which tells him that it is a real coin. He also sends (t, x) to the bank, which verifies that no such x has been spent before (no double spending) and also stores x as a ripped coin such that only the driver can spend it.
Who pays for all this checking? Not only does this require the taxi driver to have a considerable store of computational and algorithmic 'equipment' but he's also got to have a comm channel to the bank.
This don't sound cheap to execute at all...
Oh, you mean like the $5 charge that Mastercard/Visa charge merchants... this *corroborates* the stuff Hettinga has been saying about it being cheaper to use certain kinds of payment than others.