How about OTP-enabled credit cards? [1] For every transaction the customer must enter the OTP. It wouldn't serve much for subscriptions, though. [1] http://we

How about OTP-enabled credit cards? [1] For every transaction the customer must enter the OTP. It wouldn't serve much for subscriptions, though. [1] http://web.deepnetsecurity.com/products2/PocketID.asp http://web.deepnetsecurity.com/products2/PocketID.asp