Security Code

Security Code

▼ Security Code
Security code is a unique three-digit number (or four for AMEX) that appears on the back of the credit card and is used for individual authentication.

*The name and displayed parts can vary depending on the credit card company.




Security Code of AMEX

About unauthorized use and chargeback

Unauthorized use refers to the use of a credit card by a person who pretended to be the card holder. Once the unauthorized use is revealed, the credit card company initiates the chargeback*.

  • * Chargeback is the denial of payment proceeds by the credit card company to the merchant, when the card holder disagrees with the payment due to fraudulent activity. When chargeback occurs, proceeds of such transactions cannot be paid. In addition, if the clearance has been already completed by us and the merchant, and the payment cannot be offset from the recent transfer, the merchant has to pay the amount back to us. Therefore, the proceeds might not be paid to merchants, even if they have already delivered the goods or have started providing the service.

Why is it important?

Security code is used exactly according to its name as a code (cipher) of security (threat prevention). There is information that is not included in the magnetic information of the credit card. Even if the card number and the expiry date are stolen due to skimming, the security code cannot be confirmed without the card. Therefore, it is recommended as a method of individual authentication to prevent an unauthorized use of credit cards by third parties.


  • ・The security code function is available only for credit card transactions.
  • ・It does not guarantee that the card was used by the card holder, even if the security code was entered at the time of the credit card payment.
  • ・It does not guarantee the complete prevention of spoofing and other types of unauthorized uses, even if the security code was entered. Therefore, if you receive the contact regarding the chargeback, caused by an unauthorized use, you may have to accept it.