Washington Post national security reporter Ellen Nakashima speaks with Jeremy Sheridan, the assistant director of Office of Investigations at U.S. Secret Service, Dmitri Alperovitch, the co-founder and chair of the Silverado Policy Accelerator, and Tonya Ugoretz, deputy assistant director of the Cyber Division at the F.B.I, in a series of conversations about the path forward for public and private entities to secure cyberspace.