There appears to be little debate that the payment card industry's latest data security standard is improving the protection of electronic customer records. Some enterprise IT leaders, however, complain that the guidelines remain inconsistent and hard to interpret.

Finalized in September 2006, the Version 1.1 iteration of the Payment Card Industry (PCI) Data Security Standard (DSS) added new requirements to the initial set of data protection rules that major credit card issuers began demanding of their business partners beginning in 2005.

Among the modifications to the regulations -- conceived by a consortium of card industry players including American Express, MasterCard, and Visa -- the 1.1 version of the PCI standard adds so-called compensating controls that establish specific technological requirements for adherence to some of the rules.

Even those who remain critical about elements of PCI DSS agree that the standard has greatly improved data security across the retail and finance services sectors. However, some argue that the newest requirements also handcuff enterprise companies' efforts to comply with the mandate.

The standard's increasingly strict financial penalties, combined with uncertainty over the manner in which third-party auditors will interpret the rules, have made tackling PCI 1.1 a tricky proposition to manage, some large credit card processors contend.

"With 1.1 there were dramatic changes in terms of the severity of the financial penalties that could be applied and customers of ours also began writing the language directly into their contracts, which only increases the pressure," said Rich Isenberg, director of security at CheckFree, an electronic bill payment firm whose customers include major U.S. banks and financial services companies.

New requirements established in PCI 1.1 make it particularly hard for enterprise businesses that share large amounts of computing infrastructure with partners and customers to meet its demands, Isenberg said.

The security expert maintains that the regulations weren't designed with such complex enterprise environments in mind.

"The mindset in 1.1 is obviously aimed at addressing smaller retailers and outlining things that are easier for those types of companies to do, but it's almost impossible for large organizations with shared infrastructure," said Isenberg. "We're trying to understand the spirit of the requirements, but that involves working with the auditors to figure out what makes sense."

Interacting with the auditors remains one of the biggest sticking points with the standard, said the executive. Isenberg contends that it remains unclear how many of the assessment firms -- who are certified by the PCI Security Standards Council -- arrive at their conclusions about what constitutes a passing or failing grade in judging compliance with the DSS guideline.

"You're always going to have to work with the auditors, but these companies can't tell you anything about what you're doing wrong, and the PCI Board just issues a seemingly arbitrary ruling," Isenberg said. "There's no published weighting system, so it's hard to understand if you're doing the right thing and every decision costs millions."

Isenberg said that specific issues arise around PCI 1.1's demand for separation between mobile device hard drive encryption tools and Microsoft's Active Directory user account management system. Maintaining such an array in today's IT environments creates major headaches, particularly around the management of end-user encryption key data, he said.

Another impracticality of PCI 1.1, said Isenberg, is the mandate's demand for Web applications firewalls for all of the online systems maintained by companies who fall under its statutes, even those applications that are in no way linked to credit card data.

Norcross, Ga.-based CheckFree -- which claims to process over one billion transactions per year on its networks -- is working with auditors to "find a happy medium" in addressing the troublesome requirement, Isenberg said. However, the executive indicated his belief that PCI-related headaches won't disappear soon for larger, more complex businesses.