The CVV number is the card verification value or security code on a debit card. Major debit card issuers, including Visa, Discover and MasterCard, use three-digit CVV numbers, while American Express uses four digits on its prepaid debit cards. The card companies use different names for these security codes. MasterCard has the CVC2, Visa has the CVV2 and American Express has a CID.
CVV stands for Card Verification Value and it is used as an extra security measure on credit and debit cards.
The Purpose of the Code
The CVV code provides a special layer of security for your debit card when you use it remotely, such as on the Internet or over the phone. This is important because debit cards have less protection against fraud than credit cards, according to the USA.gov consumer website.
Except when you use prepaid cards, the money comes straight out of your bank account with a debit card. There's no float, which is the time between writing a paper check and when it hits and debits your account.
Location of the Code
Most debit cards, including Visa and MasterCard, show the three-digit CVV number on the back in the signature area. The security code follows the debit account number or its last four digits.
The CVV number appears on the front of American Express prepaid debit cards. It's printed to the left or right of the embossed account number. Although most debit cards contain a CVV code, not all do.
How It Works
You're typically asked to provide both your debit card account number and the CVV code when making purchases by Internet or telephone. The number proves you actually possess the card and prevents others from fraudulently providing your card number if they don't physically have the card.
If anyone tries to use your card without providing the code, the transaction is cancelled. When you give the CVV, the merchant verifies it before authorizing your purchase. It's illegal for merchants to save the CVV codes, according to Visa, so your card remains secure for future use.
It's Not a PIN
A PIN is a security code for in-store purchases and automated teller machine transactions, while the CVV is for remote use. You provide the PIN, not the CVV, to withdraw cash or make transfers from an ATM. Some debit cards require a signature rather than a PIN for in-store purchases, and some cards provide a choice of either.
PIN-based debit cards are more secure than signature cards, according to Bankrate.
Don't give out your PIN number by mistake for Internet or phone purchases.