Assured separation with easy access.
“Securing a computer system has traditionally been a battle of wits: the penetrator tries to find the holes, and the designer tries to close them.” Morrie Gasser, author of Building a Secure Computer System.
Thus it has always been and will always continue.
Espionage, be it for personal, commercial, military or political purposes is nothing new, it predates the advent of computer systems by millennia; however, it is a fact that computers and their networks have introduced many new opportunities for eavesdropping, both accidental and intentional. We call the latter ‘hacking’ but it amounts to the same thing.