Esper Remarks Defense Secretary Dr. Mark T. Esper speaks on cybersecurity and infrastructure at the National Cybersecurity Summit in National Harbor, Md., Sept. 19, 2019. SHARE IMAGE: Download Image: Full Size (0.54 MB) Tags: Cyber, Defense Secretary, Esper Photo By: Lisa Ferdinando, DOD VIRIN: 190919-D-BN624-0208.JPG Photo Gallery