Credit cards - Part 2

Credit card numbers are often misused - whether they are valid or not. A small software utility application, called Credit Card Verifier, provides a credit card number validity check. This offers the possibility of checking the validity of a credit card number offline, and do not think that it checks the existence of an account assigned to that number.
There is a drawback of using it, since there are applications that generate credit card numbers. Graham has provided such an application. So you may have a correct credit card number, as it was generated accordingly to the rules that are at the creation of credit card numbers, but it may not be assigned to any account, so using a utility application offline is not the cleverest choice.
I would say always try to use a standard online method to do this, as you can never be careful enough.