The payment card set-up involves a large number of autonomous players, and a large number of communication links -- it's a large front-line for the hackers to probe for a weak link. The two main risks are: Compromise of a financial database identity theft Hackers consistently have the upper hand, scoring big, yet the vast majority of trades remains uncompromised. The networks that run the payment card ecosystem impose a string security code, mandating that network members would abide by a published security code. Check the following slide show: Payment Card Industry -- Data Security Standard (PCI_DSS) .