That small, metallic square on your card is a computer chip. The magnetic stripes on traditional credit and debit cards store contain unchanging data. Whoever accesses that data gains the sensitive card and cardholder information necessary to make purchases. That makes unchipped cards prime targets for counterfeiters, who convert stolen card data to cash. Unlike magnetic-stripe cards, every time an EMV card is used for payment, the card chip creates a unique transaction code that cannot be used again.