The size and shape of a smart card are similar to those of a credit card, but the inside is completely different. To begin with, it has an interior — a regular credit card is just a piece of plastic. An embedded microprocessor is commonly found on the inside of a smart card. On one side of the card, the microprocessor is hidden beneath a gold contact pad. Consider the microprocessor to be a replacement for the magnetic stripe on a credit or debit card.