Codes (The History Channel, 2000/2001) This is an excellent introduction to codes and codebreaking through World War II narrated by David Kahn, author of the seminal The Codebreakers: The Story of Secret Writing.
It traces codes from early civilizations, including Egypt, the Fertile Crescent, and the ancient Egyptians. Use of codes in the West plummeted with the collapse of the Roman empire. At that time Arabs were the innovators in the transliteration and scrambling of letters. With the Renaissance came a rebirth of codes in the Western world. One of the early victims of the fatal mistake of believing that a code was unbreakable was Mary, Queen of Scots, who lost her head for this misstep.
By the 1700s every major Western power had its own code black chamber. The invention of the telegraph necessitated a rapid development of cryptography, with this pace further quickened by Marconi’s invention of radio transmission.
This provided a bonanza for codebreakers. WW I radio intercepts escalated the global codebreaking battle. Two of the great WW I codebreaking coups were the German use of tactical Russian messages to devastate Russian armies and the famous Zimmermann telegram. Room 40 of British naval cryptography used subterfuge to sanitize this German foreign message, then pass it on to the Americans. The German request that Mexico invade America and recapture territory lost in the Mexican-American War was a critical factor in America’s declaration of war against Germany.
While government investment in cryptography declined after World War I, the challenges of codebreaking increased with the invention of electrical encryptology.
A German engineer invented the ENIGMA machine, of which over 30,000 copies were bought by the German government. Poland, fearful of Germany, established a first-class cryptography department. Poles developed innovative methods by which they could replicate much of ENIGMA’s capabilities. Just before Germany invaded Poland, the British and French were invited to inspect Poland’s codebreaking operation. They were permitted to smuggle key machines out of Poland just before the outbreak of World War II.
With this jump start from the Poles, the British, at Bletchley Park, were able to achieve great success in deciphering ENIGMA messages. Alan Turling’s intuitive brilliance was a major factor in British reading of virtually all ENIGMA messages.
Though the documentary mentions the importance of these intercepts to Allied successes in the Battle of the Atlantic, North Africa, and D-Day, one must go to other sources for the specific details of these successes.
In the United States, after World War I, cryptography was severely downgraded. Mostly through the efforts of William Friedman and his small band of dedicated cryptographers, was the U. S. still in the cryptography game. No mention is made of how Secretary of State Henry Stimson, upon learning that H. O. Yardley’s Black Chamber was deciphering foreign messages, ordered that the group be dissolved. His reason: “Gentlemen do not read other gentlemen’s mail.”
William Friedman of the Army Signal Corps worked persistently on Japanese codes. His greatest breakthrough was deciphering the PURPLE code, which was a high-level Japanese diplomatic code. No mention is made of how these intercepts were used (and misused) during the period before Pearl Harbor.
Major attention is given to the work of Lt. Commander Joseph John Rochefort and his tiny band of cryptographers in Pearl Harbor. Focusing on Japanese naval codes, they scored major successes, although frequently they were deterred by unknown geographic references and monthly code changes. Their work contributed to the U. S.’s remarkable victory at Midway which resulted in a Japanese defeat that was the harbinger of the gradual American rollback of Japanese military forces throughout the Pacific.
Mention is also made of the Navajo Windtalkers. Because the Navajo language was known by only thirty white Americans and no foreigners, the Marines used Navajos for combat transmissions. This provided a major tactical advantage on Guadalcanal, Iwo Jima, and elsewhere.
Although books address government cryptology in the post-WW II period, this is omitted in the documentary. One writer suggests that David Kahn, because of his close work with government, was restricted in what he could say, even in the updated version of his The Codebreakers.
Considerable focus was accorded private efforts to provide encryption devices and the fight by the National Security Agency (created by President Truman in 1952) to prevent general access to ‘public key cryptography.’ Mr. Kahn concludes that the technical development of secure codes may lead, in the absence of human error, to the slow death of codebreakers.
This statement was made before the latest Iraq war and the Patriot Act, which provided NSA carte blanche to invade the privacy of individuals in the name of national security.