How does my online banking fob work?
September 24, 2008 4:48 PM Subscribe
How does my online banking fob work? Does it get numbers over-the-air or does it generate the according to some math I don't understand? Background: to access my bank account on the web, I need to use the little electronic fob CitiBank sent me when I registered for online banking. The device generates a six-digit number every minute or so. But where does that number come from? Is the fob generating or receiving it?