CVV information is stored in the track of magnetic stripe bank card. According to the information such as card number, track main account number and logo code of issuing bank, it is encrypted by special encryption algorithm defined by each bank, and every step is encrypted by CVKA technology to get verification code. Because the encryption algorithms of different banks are different, some fake cards illegally made by using the obtained bank card information can be identified and cannot be used when the issuing bank decrypts them.
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In order to prevent more and more crimes of stealing credit card information, major banks have given specific tips to card owners. For example, in a letter sent to the credit card owner, a bank emphasized that the credit card number, expiration date and other information are important documents for the transaction. Please take good care of personal information such as card number and expiration date, and don't tell others about the credit card. There are also bank reminders that when applying for a credit card, you can indicate the purpose of use in a prominent position, such as "only for applying for a bank credit card, and the copy is invalid" to prevent the information from being used for other purposes.