Credit and debit cards use a cryptographic configuration commonly known as CSC (Card Security Code), CVV, (Card Verification Value), CW2, CVC2 or a CID number to provide maximum security for online payments and cut down on fraud.
This security code consists of 3 or 4 numbers which you can find on the back of your MasterCard or VISA cards, or on the front of American Express cards.
This security code provides added value for this payment method. You usually need It when you shop in online stores, instead of using your PIN. PIN numbers are reserved for transactions in physical stores and ATMs.
This code is secure as it is printed on the card and is not encrypted on the metallic strip or NFC (contactless) chip. This means it cannot be read or scanned by a device to replicate the data.
This system was developed in the UK in 1995. Initially, the cards had 11 alphanumeric characters, rather than 3 or 4 digits. In 1997, MasterCard implemented the code in its payment protocol and VISA introduced it in the United State, in 2001, while American Express started using the CSC in 1999, in response to the impact of online shopping and card fraud suffered by some of their customers.
Depending on the financial institution associated with the card, you may have to validate your online payments and purchases using your CVV code and also a second random security code sent by the bank's IT security system to your mobile phone to authorise the payment or transaction. These two codes protect both the bank and the customer making the payment.