I applied for a youth power credit card from Bank of Communications last month and received it today. When I signed my name in the signature column, I found that the numbers were the same. This is to prevent your card from being forged by criminals. The number immediately after the last digit of the card number is the security number, that is, CVV code. When you use your credit card for TV and telephone shopping and online transactions, the special merchants will ask you to enter this number as needed to verify your identity. Therefore, after receiving a new credit card, you should remember your CVV code and immediately cross it off the card to prevent it from being stolen by others.