使用信用卡在线付款通常需要CVV/CVC码，那么，什么是CVV/CVC码呢？
CVV: Card Verification Value
CVC: Card Verification Code
CVV，也可以称作CSC，CVV numbers are also known as CSC numbers (“Card Security Code”)
CVV位于信用卡背面白色签名条后方，一般是三个数字。The CVV/CVC code is located on the back of your credit/debit card on the right side of the white signature strip; it is always the last 3 digits in case of VISA and MasterCard.
