Imagine receiving a notification about suspicious charges on a credit card you haven’t even received yet. How could that happen? While it sounds surprising and unsettling, it's increasingly common due ...

The numbers on a credit card help identify the credit card network, the company that issued the card and the cardholder. Credit card numbers are either 15 or 16 digits, with each digit having its own ...

All mainstream credit card numbers obey a mathematical trick designed to catch the most common typos. It’s called the Luhn algorithm, named after IBM researcher Hans Peter Luhn, who patented it in ...