A CVV number is a credit card security feature used to prevent internet or telephone use of a credit card by a nonowner. CVV stands for card verification value. The feature is also known as a CVN (card verification number), CVC (card verification code), a CVVC (card verification value code), CSC (card security code), CCV (card code verification) or a V-Code (verification code). The number is printed on credit cards but does not get stored when the card is used. Thus, the only way to have access to the number is to be in physical possession of the card. When a CVV number is required, a person can have all of your credit card information but still not be able to remotely purchase items on your dime. CVV numbers are an extra level of protection against hackers stealing the financial information that merchants store on their customers.
American Express cards display a printed, four-digit CVV on the front right side of the card, while Visa, MasterCard and Discover print a three-digit CVV on the back of the card next to the signature strip.
Requiring CVV numbers prevents hackers and merchant employees who gain access to customer credit card information from making internet and telephone transactions, when identification can't be verified.
CVV numbers cannot guard against unauthorised telephone and internet purchases by a thief in possession of a credit card.
Besides the printed CVV security numbers, another code exists on the card, encoded invisibly on the magnetic strip.
CVV numbers should not be written anywhere but on the credit card, nor should a person scratch out the numbers on the card. In case of theft, the card issuer should be notified to immediately cancel the card.