The blog post came after Google for misleading customers about its compliance with the standard.

At issue is whether Google Apps has achieved certification under the Federal Information Security Management Act. FISMA set a stringent security standard that some federal agencies must require their vendors to comply with.

On Tuesday, Microsoft pointed out recently unsealed U.S. Department of Justice court documents that say Google Apps for Government does not have FISMA certification, even though the company's websites say it does.

"Let's look at the facts," Eran Feigenbaum, director of security for Google Enterprise, wrote on Wednesday. He said Google Apps received FISMA certification from the General Services Administration in July 2010. Google has since started using the name "Google Apps for Government" to describe the service and has added two "security enhancements," he wrote.

"In consulting with GSA last year, it was determined that the name change and enhancements could be incorporated into our existing FISMA certification. In other words, Google Apps for Government would not require a separate application," Feigenbaum wrote.