The CVV2 number of a credit or debit card is generated by the card issuer. This process uses an algorithm (used for all CVV variants) that requires a primary account number, a four-digit expiration date, a three-digit service code, and a pair of DES keys, explains UniBul.
The CVV2 is a second-generation CVV. The CVV number may also be called the CSC, CVD, CVVC, CVC, V-Code or CCV, depending on the card association, according to HostGator. A CVV2 is the last three digits of the number that is printed on the back of a credit or debit card, with the exception of American Express cards, where it is a standalone four-digit number printed on the front. A card may have both a CVV and a CVV2. The purpose of a CVV2 is to enhance fraud protection and help in validating that the customer has the card in their possession, and that the card number is legitimate, explains Meetings Etc.
According to UniBul, there are two types of card verification value, depending on where the information is stored. A CVV code is stored in the card's magnetic strip, while an iCVV (Integrated CVV) code is stored in the card's chip. If a card features both a magnetic strip and a chip, the CVV code can be stored in both, or the issuer can choose to calculate different values. For iCVV validation, the service code in the algorithm is replaced with the value 999.