CVV2 refers to a type of security code used as a safety feature to prevent credit card fraud. Card security codes (CSCs) may also be called Card Verification Data (CVD), Card Verification Value (CVV or CVV2), Card Verification Value Code (CVVC), Card Verification Code (CVC or CVC2), Verification Code (V-Code or V Code) or Card Code Verficiation (CCV).A security code is not the actual credit card
. account number. The codes are usually located on the back of the credit card, depending on the issuing bank's procedures. Three types of encoding are used to generate CSCs, and the codes are verified using a separate validation method, called the Luhn algorithm.The first type of CSC is CVC1 or CVV1, which is encoded on the credit card's magnetic stripe. During a transaction these security codes are verified by the card's issuing bank. However, CVC1 codes are vulnerable to skimming, which is the practice of duplicating the card's magnetic strip, which would provide the thief with the security code, along with the cardholder's name and account number.A second type of security code, called the CVV2 or CVC2 is used in transactions where the credit card is not present, such as those that occur on the Internet or by mail, fax or telephone. These CSCs are not encoded on the card's magnetic strip, making them less prone to certain types of credit card fraud.Contactless cards containing RFID chips are the third type of CSC encoding technique. These cards use dynamic CVVs or iCVVs to generate CSCs.CVV2 codes are generated at the time the card is issued, using an encryption of the credit card's account number, expiration date and service code. Generally only the bank is in possession of the encryption keys, or Card Verification Key (CVK). However, hackers and other programmers may attempt to engage in credit card fraud by decrypting CSC codes, generating fake CVV2s or creating fake credit cards using the issuing bank's encryption keys. All of these activities are illegal and could result in arrest and imprisonment.More reference links: https://www.pcisecuritystandards.org/security_standards/index.php http://ptmoney.com/credit-card-generator/
