Chip and signature describes a form of credit card authentication coming into use in the United States. Traditionally, American credit cards were authorized for use via the data on magnetic stripes on the backs of the cards. As their name implies, chip-and-signature cards have a chip embedded within them, and the authority to use them is verified by signature. Chip-and-signature cards are an advancement in security over magnetic stripes, but not as secure as chip-and-PIN cards, which are verified with a PIN number.