Ensuring a safe payment method is considered one of the essential aspects for credit card payments.
This problem stems from the nature of internet, which is a relatively insecure means of communication.
All data entered through a keyboard reach a computer located many thousands of kilometres away and course through a great number of cables, many different physical means and are handled by a noteworthy amount of computers. Anyone who has access to those could theoretically spy communications.
There are those sustaining that the safety problem is a false one arguing that the digital world is much safer than the analogical one. This is based on the so-called "security through obscurity"; meaning safety through scarce clarity: there are so many email messages coursing through internet every day that it is virtually impossible for a hacker to successfully find those that contain credit card numbers.