Credit Card Security Code Description
Due to the amount of credit card fraud over the internet, banks increasingly require this information to process credit card orders online. Your benefit is that it prevents any fraudulent charges using your credit card, i.e. no one can pick up an old receipt of yours and use that info to fraudulently use your credit card.
Note: The digits are printed on your card, rather then stamped in the plastic like the digits in your credit card number.