Credit scoring company Experian explains: Credit card security codes, or verification numbers, are three- or four-digit numbers that banks and other lenders use to provide an extra layer of protection against fraud.
This number is also known on various cards such as a card verification number or value (CVV), card security code (CSC), card authentication code (CVC), and card identification (CID). Understanding how these transactions work will help you complete transactions more quickly, including when making a phone call to a card issue company or making an online purchase.
On most cards, the security code is found on the back in the signature area or just to its right. It may appear in a white box that is the last part of the signature line, or it may only appear at the end of the signature line.
On an American Express card, the card verification number is a four-digit sequence that appears black on the front of the card, just above the last two digits of your credit card.
Unlike the floating numbers that make up your credit card number, your verification number is flat, printed only in ink.
Some cards, such as Citibank’s ThankYou Preferred card, have a credit card number, expiration date, and CVV number on the back of the card.
What is it used for?
What if someone uses their smartphone to take a picture of your credit card, such as when the credit card is lying on a waiting desk served by a restaurant server? The person currently has your name as on your card, your card number, and your expiration date.
To prevent someone from charging to your card, who only has a picture of the front of the card (or who has seen the information and remembered it) and not the physical card, the lender uses a security code. This allows the seller to request it, often asking the customer to flip the card to read it, increasing the likelihood that the person making the transaction has the card in hand.
Also, even if you allow your business to store your credit card information for future purchases, companies aren’t allowed to store your numbers. Therefore, if the store is hacked, the hacker does not have your security number and there will be fewer places to use your credit card.
It’s not your PIN.
Your CVV is not your personal identification number, it is another layer of protection. A PIN is something you choose and use when asked. PINs are often used for debit card transactions or when you are using credit card services or online apps. Unlike the CVV assigned to you, a PIN usually has to be requested or sent by the card owner.
Other names for card verification numbers
Other names of security codes include card security code, or CSC; card authentication value, or CVV, for Visa cards; card authentication code, or CVC, for MasterCard card; and card identification, or CID, for American Express and Discover cards.