November 20, 2009 -- Security experts raised privacy concerns after a U.S. National Security Agency official revealed that the Agency collaborated with Microsoft during the development stage of Windows 7. The revelation was made in a prepared statement by NSA information assurance director Richard Schaeffer, before the U.S. Senate’s Subcommittee on Terrorism and Homeland Security, which operates under the Judiciary panel. Speaking during a hearing on cybersecurity on November 17, Schaeffer acknowledged that the NSA drew on its “unique expertise and operational knowledge of system threats and vulnerabilities to enhance Microsoft’s operating system security guide”. Schaeffer's prepared statement is available on video here (forward to 32nd minute). Commenting on Schaeffer’s revelation, security experts and watchdog groups expressed privacy concerns, citing the Agency’s controversial domestic intelligence operations in recent years. Marc Rotenberg, executive director of the Electronics Privacy Information Center (EPIC), said “the obvious concern is [that the NSA has built] in back doors that enable tracking users and intercepting user communications”. This is the third time in recent years that the NSA is found to have collaborated with Microsoft in developing operating systems. The secretive Agency worked with the U.S.-owned vendor on Windows 9X, Windows XP, Windows 2000, and Windows Vista.