Is someone listening in to secret communication? Copying sensitive data?

Keeping communication safe from prying eyes and ears. It's why the ancient Greeks had their whispers. It's what inspired the enigma machine of World War II, and today, digital encryption. But all of these could be compromised. The problem is when someone listens in on secret communication, or ...This is an NSF Multimedia Gallery item.

Source: NSF Multimedia Gallery - September 4, 2020 Category: Science Source Type: video