Smart card. Close-up of part of a smart card or memory card. Smart cards are used to store information electronically. Here information is stored on an in-built microprocessor chip (gold). Similar in size to a credit card, smart cards may contain a central processing unit which can store, secure and act on information that can be added or erased as required. Alternatively, the card may be used to store fixed information, such as an employee's personal details. The chip protects the stored information from damage or theft, making a smart card much more secure than a magnetic stripe card, which carries information on its outside where it can easily be copied.