Player Embed Code: Download Embed Share Senior DOD Information Security Leader Holds Fireside Chat at Billington CyberSecurity Summit Defense.gov Oct. 8, 2021 | 16:50 David McKeown, Department of Defense senior information security officer and deputy chief information officer for cybersecurity, provides his unique perspective overseeing one of the largest and most complex networks in the world during a fireside chat hosted by the Billington CyberSecurity Summit.