Compliance with the Payment Card Industry (PCI) Data Security Standard (DSS) helps to alleviate vulnerabilities and protect cardholder data.
The PCI DSS applies to all entities that store, process, and/or transmit cardholder data. It covers technical and operational system components included in or connected to cardholder data. If you are a merchant who accepts or processes payment cards, you must comply with the PCI DSS.
View PCI-DSS standards at http://www.pcisecuritystandards.org