The Credit Card Verification Code helps minimize fraud in transactions
where the credit card is not physically present, such as internet transactions.
It protects both you, the consumer, and the merchant.
Visa and Mastercard use a 3-digit number on the back of the card, while
American Express uses a 4-digit code, printed on the front.
To locate the code on your Visa or Mastercard, find the 3-digit number
printed on the back of your card toward the end of the strip that contains
your account number.
To locate the code on your American Express, find the 4-digit number
print on the front of your card at the end of your account number.