February 13, 2011, 11:09 PM PST | Length: 237
They're a modern-day must. Anyone who's ever forgotten their credit card at home or worse, lost it, knows exactly how crucial that piece of plastic truly is. With rampant fraud and ID theft though, most cardholders are equally aware of the risks. But what if the account number on your card disappeared when not in use? ZDNet correspondent Sumi Das explores payment innovations from Dynamics, Square and Bling Nation.