However, while the service didn't require a new application, it apparently did require re-certification. In testimony in front of the U.S. Congress on Tuesday regarding the issue, Dave McClure from the GSA said that when products change, vendors have to recertify them, report. He confirmed that the agency is going through a recertification process for Google Apps for Government, which he called a "subset" of the original service, Google Apps Premier, that was initially certified.

The disagreement, then, appears to be over whether Google should say Google Apps for Government is FISMA certified while it is going through the recertification process. The company firmly argued it should.

"FISMA anticipates that systems will change over time and provides for regular reauthorization--or re-certification--of systems," Feigenbaum wrote in the blog post. "The system remains authorized while the changes are evaluated by the GSA."

"We've been very transparent about our FISMA authorization," he wrote. "Our documentation has always been readily available for any government agency to review, and dozens of officials from a range of departments and agencies have availed themselves of the opportunity to learn more about how we keep our customers' data secure.

"We'll continue to update our documentation to reflect new capabilities in Google Apps," he wrote.