KW-37
The KW-37, code named JASON, was an encryption system developed In the 1950s by the U.S. National Security Agency to protect fleet broadcasts of the U.S. Navy. Naval doctrine calls for warships at sea to maintain radio silence to the maximum extent possible to prevent ships from being located by potential adversaries using radio direction finding. To allow ships to receive messages and orders, the Navy broadcast a continuous stream of information, originally in Morse code and later using radioteletype. Messages were included in this stream as needed and could be for individual ships, battle groups or the fleet as a whole. Each ship's radio room would monitor the broadcast and decode and forward those messages directed at her to the appropriate officer.
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