Bank verification code, also known as CVV number, is a set of numbers on a credit card or debit card. This set of numbers is usually contained in the credit card or debit card itself, and can also be found in the bill or online account of the credit card or debit card. The function of bank verification code is to confirm the security of credit card or debit card when the bank makes online payment or telephone payment.

The bank verification code is generally three digits, and sometimes it may be four digits. The location, size and shape of the bank verification number vary from card issuer to card issuer. However, either way, the bank verification number is an important security feature. If your bank verification number is accidentally leaked, your credit or debit card account may be stolen.

Therefore, when you buy goods or services, websites or businesses usually ask you to enter the bank verification code. If you accidentally disclose the bank verification number to others, your bank account may be at risk. So protecting your bank verification number is equivalent to protecting your account. Don't let people you know or don't know know know or use your bank verification number.