The 15- or 16-digit credit card number on the front or back of your card helps authenticate every purchase you make, whether you’re buying something in person or online.

#4 The scammer then reads your credit card number to you (that's a nice touch, isn't it?) #5 To verify that you have the card in your possession, you need to confirm the three digits on the back.

You can use these generated numbers to protect your credit card’s actual number. If one of these generated numbers gets leaked, you can quickly delete it and generate a new number.