Page:Friedman Lectures on Cryptology.pdf/8

Rh Rh and had given ample warning of the Jap's sneak attack, if only U.S. brass hats had been smart enough to realize it. Now, General Marshall continued the story of '' magic:


 * 1) 'It had enabled a relatively small U.S. Force to intercept a Jap invasion fleet, win a decisive victory in the Battle of the Coral Sea, thus saving Australia and New Zealand.
 * 2) 'It had directed U.S. submarines unerringly to the sea lanes where Japanese convoys would be passing.
 * 3) 'It had given the U.S. full advance information on the size of the Jap forces advancing on Midway, enabled our Navy to concentrate ships which otherwise might have been 3,000 miles away, thus set up an ambush which proved to be the turning-point victory of the Pacific war.
 * 4) 'By decoding messages from Japan's Ambassador Oshima in Berlin, often reporting interviews with Hitler, it had given our forces invaluable information on German war plans.'"

Time goes on to give more details of that story, to which I may later return but I can't leave this citation of what cryptology did toward our winning of World War II without telling you that the account given by Time of the achievements of Magic makes it appear that all the secret intelligence gained from our reading Japanese messages was obtained by using that "harmless little machine" which Time said was used in Tokyo by the Japanese Foreign Office. I must correct that error by explaining first that Magic was not the name of the machine but a term used to describe the intelligence material to which the machine, among other sources, contributes and then by telling you that the secret information we obtained that way had little to do with those portions of the Magic material which enabled our Navy to win such spectacular battles as those of the Coral Sea and Midway, and to waylay Japanese convoys. The naval parts of Magic were nearly all obtained from Japanese naval messages by our own very ingenious U.S. Navy cryptanalysts. At that time, I may tell those of you who are new, the Army and Navy had separate but cooperating cryptologic agencies and activities; the United States Air Force was not yet in existence as an autonomous and separate component of the Armed Forces, and work on Japanese, German, and Italian Air Force communications was done by Army cryptanalysts, admirably assisted by personnel of what was then known as the Army Air Corps.

It is hardly necessary to tell you how carefully the Magic of World War II was guarded before, during, and after the war until the Congressional Inquiry brought most of it out in the open. Some remaining parts of it are still very carefully guarded. Even the fact of the existence of Magic was known to only a very few persons at the time of Pearl Harbor &mdash; and that is an important element in any attempt to explain why we were caught by surprise by the Japanese at Pearl Harbor in a devastating attack that crippled our Navy for many months. Let me read a bit from page 261 of the Report of the Majority of the Joint Congressional Investigation of the attack:

"The Magic intelligence was pre-eminently important and the necessity for keeping it confidential cannot be overestimated. However, so closely held and top secret was this intelligence that it appears that the fact that the Japanese codes had been broken was regarded as of more importance than the information obtained from decoded traffic."

Time says, in connection with this phase of the story of Magic during World War II:

"So priceless a possession was Magic that the U.S. high command lived in constant fear that the Japs would discover the secret, change their code machinery, force U.S. cryptographers to start all over again."

Now I don't want to overemphasize the importance of communication intelligence in World War II, but I think it warranted to read a bit more of what is said about its importance in the Report of the Majority. The following is from p. 232:

" ... all witnesses familiar with Magic material throughout the war have testified that it contributed enormously to the defeat of the enemy, greatly shortened the war, and saved many thousands of lives."

General Chamberlin, who was General MacArthur's operations officer, or G-3, throughout the war in the Pacific, has written: "The information G-2, that is, the intelligence staff, gave Rh