A big change is happening inside your wallet. U.S. banks, tired of spending billions each year to pay back fleeced consumers, are in the process of replacing tens of millions of old magnetic strip credit and debit cards with new cards that are equipped with computer chips that store account data more securely.
 
By autumn, millions of Americans will have made the switch from the old magnetic strip cards. That 50-year-old technology, replaced in most of world, lingers on the back of U.S. cards and is copied easily by thieves, leaving people vulnerable to fraud. This entire switch is a massive undertaking. Roughly half of all U.S. credit and debit cards will be replaced by the end of the year. Tens of thousands of individual merchants need to upgrade their equipment to allow for "chip-and-sign" transactions instead of "swipe-and-sign" ones.  If the stores aren't ready, they could be on the hook to cover the cost of fraud.
 
Here's how the new cards work and how the switch could affect you at the checkout counter:  The biggest difference between your old card and your new one is the metal chip embedded on the front, which means your personal data are much safer. The chip assigns a unique code for every transaction made on your card. Even if a thief acquired that code, it couldn't be used to make another purchase. "The chip technology is designed to prevent copying of the card," said Ellen Richey, vice chairman of risk and public policy at Visa.