Great question

I don't know too much about the technology. I think that traditional cards at least just have a magnetic strip that encodes various numbers including the pin, account, routing, bank etc. and then the atm or pos system contacts the bank's server to get the rest of the info. Perhaps the newer cards with chips do the same thing but encrypt the pin? Maybe they do more?

In any case, the Cyclos system already has a module that allows people with cell phones to connect directly and send transactions through their phones and I could imagine using a future cell phone/pda/computer to store/exchange digital dollars quite easily.

Perhaps Paul will weigh in on his vision.
