PCI Compliance Introduction

Payment data security could have been left to individual businesses to figure out. It wasn’t. The Payment Card Industry made a deliberate decision that the stakes were too high and the incentives too misaligned to trust each merchant or vendor to invent their own approach. The result is the PCI Data Security Standard (DSS)—a published specification that applies to every member, merchant, and service provider that stores, processes, or transmits cardholder data.

The scope is broad by design. PCI-DSS requirements extend to every system component within the payment application environment: any network device, host, or application that sits in, or connects to, a network segment where cardholder data lives.

Why this series exists

This series guides software development projects through what PCI-DSS compliance actually demands in practice. It covers both the PCI initiative and the Payment Application Data Security Standard (PA-DSS), then works through specific installation, configuration, and ongoing management practices for PA-DSS certified applications operating in a PCI-DSS compliant environment.

PCI-DSS vs. PA-DSS: understanding the distinction

One concept worth getting straight early is the difference between PCI-DSS compliance and PA-DSS validation. They are related but distinct, and they apply to different parties.

As a software vendor, our responsibility is to ensure our solution conforms to industry best practices when handling, managing, and storing payment-related information. PA-DSS is the standard against which a payment application is tested, assessed, and certified. It governs the software itself.

PCI-DSS compliance is something the merchant obtains. It is an assessment of the merchant’s actual server or hosting environment—not the software running on it. Achieving PCI-DSS compliance is the joint responsibility of the merchant and their hosting provider, who together must implement compliant server architecture with proper hardware and software configurations and access controls.

PA-DSS certification is designed to ensure that a certified solution will help merchants achieve and maintain PCI-DSS compliance—specifically in how the solution handles user accounts, passwords, encryption, and other payment data. The certification is a promise that the software won’t make compliance harder than it needs to be.

Reference documents

The PCI Security Standards Council publishes the primary standards and guidance: the Payment Application Data Security Standard (PA-DSS), the PCI Data Security Standard (PCI-DSS), and the OWASP secure development guidelines that inform much of what both standards require.