Secure communication

Secure communication is when two entities are communicating and do not want a third party to listen in. For that they need to communicate in a way not susceptible to eavesdropping or interception. Secure communication includes means by which people can share information with varying degrees of certainty that third parties cannot intercept what was said. Other than spoken face-to-face communication with no possible eavesdropper, it is probably safe to say that no communication is guaranteed secure in this sense, although practical obstacles such as legislation, resources, technical issues (interception and encryption), and the sheer volume of communication serve to limit surveillance.

With many communications taking place over long distance and mediated by technology, and increasing awareness of the importance of interception issues, technology and its compromise are at the heart of this debate. For this reason, this article focusses on communications mediated or intercepted by technology.

Also see Trusted Computing, an approach under present development that achieves security in general at the potential cost of compelling obligatory trust in corporate and government bodies.

In 1898, Nikola Tesla demonstrated a radio controlled boat in Madison Square Garden that allowed secure communication between transmitter and receiver.

One of the most famous systems of secure communication was the Green Hornet. During WWII, Winston Churchill had to discuss vital matters with Franklin D. Roosevelt. At first, the calls were made using a voice scrambler as this was thought to be secure. When this was found to be untrue the engineers started work on a whole new system, the Green Hornet or SIGSALY. Anyone listening in would just hear white noise but the conversation was clear to the parties. As secrecy was paramount, the location of the Green Hornet was only known by the people who built it and Winston Churchill, and if anyone did see him entering the room it was kept in, all they would see was the Prime Minister entering a closet labeled 'Broom Cupboard.' It is said that because the Green Hornet works by a one-time pad it cannot be beaten.

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