First, PCI DSS stands for Payment Card Industry Data Security Standard. It started out as a series of five separate programs, namely: American Express Data Security Operating Policy, Discover Information and Compliance, JCB Data Security Program, MasterCard Site Data Protection and Visa Card Information Security Program.

While each program was unique and came from different (in some cases, competing) brands, the overall aim was the same throughout: to ensure merchants meet minimum levels of security in storing, processing and transmitting cardholder data in order to better protect card issuers.

The five separate but similar policies were eventually collated in 2004 when the PCI DSS was created. Soon afterward, each company aligned their own policies to correlate with that of the new industry standard.

Updates
Since its creation in 2004, the PCI DSS policy has undergone numerous updates in order to keep on top of recent developments, whilst improving clarity and flexibility. One of the largest of these updates came in 2009 when the PCI DSS was amended to deal with wireless transactions. This brought about the recommendation for all firms to use a Wireless Intrusion Prevention System to remain PCI DSS-compliant in the new marketplace.

Another sizeable update came in 2010 regarding call centre work. Often in call centre work, customers are asked to read out their card information, including the CVV code, to the person on the other end. Furthermore, the majority of calls are recorded for security and training purposes, meaning that others in the call centre can gain access to the recordings without needing to undergo security clearance. This made the process of 'skimming' details incredibly easy.

This practice leads to revisions into procedure for call centre recordings. Now, call centres are not permitted to store recordings that include the three-digit CVV number if they can be queried.

Requirements
When in operation, PCI DSS is aimed at providing 12 requirements to cover six main control objectives. The first objective is to build and maintain a secure network. To ensure compliance, businesses need to install and maintain a firewall to protect cardholder data. They must also not use vendor-supplied defaults for their security measures (such as using 'password', the business name or '0000' as a passwords or codes).

Secondly, in order to protect cardholder data, businesses must protect any information they have stored on system and ensure that any data that is transmitted across open, public networks is comprehensively encrypted.

The third control objective is to maintain a vulnerability management programme. To attain compliance, businesses must use and maintain anti-virus software on all their systems that may otherwise be affected by malware. This must be kept up-to-date at all times to guarantee protection against even the newest threats. Businesses must also develop and maintain secure systems and applications across the network.

To implement strong access control measures (the fourth objective), businesses must restrict access to cardholder data by business on a need-to-know basis. They must then assign each different computer user with a unique ID so usage can be tracked back to each individual. Firms must also restrict physical access to cardholder data.

The fifth objective tasks firms with regularly monitoring and testing their networks. To ensure compliance here, businesses must track and monitor all access to network resources and cardholder data, as well as regularly test their security systems/processes.

Lastly, businesses must ensure they maintain a policy that addresses information security.

Keeping up to date with PCI DSS can be a large undertaking for a brand, but high-profile cases of firms that have seen their security breached - as well as the fall-out that came afterwards - shows just how important it is to stick closely to the best practice guidelines.

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