The outbreak of World War One was accompanied by new strategies, innovations, and inventions that developed modern warfare. World War One saw the widespread use of everything from artillery to machine guns and airplanes to submarines. World War One also saw the world’s most powerful navy, Great Britain’s Royal Navy, pitted against the up and coming German Imperial Navy. From Britain’s effective use of the naval blockade to Germany’s terrifying unrestricted submarine warfare, both sides were constantly looking for new strategies to implement.
One of Great Britain’s most important naval developments was the founding of the top-secret Office of Naval Intelligence, better known as Room 40. Specializing in cryptography, “the science of writing in secret code” in order to hide sensitive information, Room 40’s cryptanalysts worked around the clock to break the secret code. Decryption is vital in secret transmissions concerning strategic war movements, as the enemy will be looking to intercept information concerning movements and positioning. Great Britain was aided in that the German Navy started the war with three primary codes, and within four months the British Admiralty possessed physical copies of all three of them.
The primary codebook was the Signalbuch der Kaiserlichen Marine (SKM), which had been seized by the Imperial Russian Navy on August 26, 1914 from the German light cruiser SMS Magdeburg. The second codebook was the Verkehrsbuch (VB), found by a British trawler in the North Sea. The third codebook was the Handelschiffsverkehrsbuch (HVB), captured by the Australians early in the war. The VB was used at sea by German flag officers, while the HVB was used by the entire High Sea Fleet, including submarines, Zeppelin airships, and outposts.
Room 40 was founded in August 1914 when Rear Admiral Henry Oliver, then the Director of National Intelligence, realized the need for a concentrated focus on encrypted German wireless telegraphy. Oliver requested that Director of Naval Education Sir Alfred Ewing develop an organization to concentrate on decrypting the communications. Ewing obliged, as he had a strong interest in codes and ciphers. Arthur Ward described Room 40 an “extraordinary band of amateurs,” with clergymen, stockbrokers, bankers, naval-school masters, and university professors. The group received the name of Room 40 from the block of offices they occupied in the Old Building of the Admiralty.
The British seizure of the aforementioned German codebooks enabled them to decrypt German naval communications intercepted by the system the Admiralty had put into place. This system included a network of wireless telegraphy coastal listening posts, which “intercepted a wealth of German operational naval signals in the 400-to-800 meter wavelength range.” The British Admiralty had eight operational listening ports by May 1916. Germany had been severed from direct cable communication from the first hours of the war by the Telconia,...