TheCodeBreakers
CIPHER is the language of spies—and usually they must talk in whispers.
A spy's success, his very existence, depends on his not being seen or
heard. Sending messages in obviously cryptographic form would alert
counterespionage to him as effectively as wearing a cloak and dagger. Yet
he must transmit, else he is useless. So he eschews the overt methods of
secret communications for the covert. He resorts to open codes, hollow
heels, invisible inks, microscopically small missives—the stegano-graphic
methods that conceal the very fact that a message is being sent. He seeks
to communicate unnoticed.
And to block this very attempt and root out the enemy within,
governments erect great filters at their mail and cable ports of entry to
prevent and detect these clandestine communications. These sieves,
which let innocent messages flow through, are the censorship
organizations.
Descended in a sense from the black chambers of the 1700s, they are