The following is the text of "World War II Code-Breaking Exploits Unveiled By Retired IBM Engineer After 50 Years Of Secrecy," an IBM Europe/Middle East/Africa Corporation press release distributed on February 12, 1992.
Complete disbelief that their rapidly changing codes could ever be deciphered made the German and Japanese militaries complacent and vulnerable throughout World War II, says a retired IBM engineer who helped develop a top-secret IBM computer that decoded intercepted radio messages for the U.S. War Department.
Stephen Dunwell, 78, waited 50 years to go public with selected information on the black art of how a small team of engineers "hotrodded" commercial IBM punch card machines with special relay calculators. Using data processing techniques, they were able to obtain from machines running at a speed of 150 cards a minute the equivalent of more than one million comparisons each second -- an astonishing feat unheard of, in public, until now.
Throughout the war, the Allied forces intercepted thousands of coded radio signals sent from German U-boats, Pacific naval fleets, and other strategic military and diplomatic sources. The messages were relayed to various intelligence groups including Alan Turing's now-famous decoding Enigma "bombe" machines in the U.K., and to the U.S. War Department's new cryptographic center based in the Washington, D.C. area.
Unknown to enemies of the Allied forces, IBM machines and electronic "bombes" rapidly decoded radio messages and released them to teams of "cryptanalysts," whose ranks swelled to several thousand by the war's end. The U.S. and British cryptanalysts worked day and night to distill and analyze messages, looking for needles of intelligence in an information haystack that would eventually influence major world events. And, in the cloak-and-dagger world of espionage, counter-intelligence efforts were made to relay misinformation back to the enemy.
In 1942, William Friedman, the mastermind whose team of cryptanalysts broke "Purple," the Japanese diplomatic code used during the 1941 bombing of Pearl Harbor, recruited IBM product planner Dunwell from the company's Endicott, N.Y., Laboratory.
Dunwell refuses to speculate on why decoded clues from the now-famous Pearl Harbor bombing were ignored by the U.S., but volunteers that the catastrophe became the catalyst for the U.S. to give "carte blanche" to the Army Signal Corps -- a predecessor of today's National Security Agency (NSA) -- to cultivate intelligence agents to analyze enemy radio messages.
"Friedman believed that people who broke codes could best make codes," says Dunwell. "He also foresaw the need to develop high-technology machines to assist with efforts to decipher and encipher codes, and successfully appealed to IBM founder and president Thomas J. Watson, Sr., for his pledge of support."
Within days of being tapped to be technical director of the machine branch of the new U.S. cryptographic center, Dunwell found himself out of IBM and in the Army with a gun strapped to his waist, and unlimited funding and resources, Between round-the-clock efforts to adapt punch card-fed relay computers to new uses, Dunwell found time to woo and marry a former school teacher who became the secretary of the cryptographic center's Commandant. "We fitted our honeymoon into a working trip," he says. "By 1943, the machine was designed, built, and working."
While the Army Signal Corps never formally had Dunwell take vows of secrecy, the engineer explains that self-enforced censorship and discretion was "understood," even if keeping the secret of the decoders meant risking the lives of Allied servicemen such as those who had to maintain radio silence during bombing runs over Germany. Dunwell says that he only wanted information from the military on a "need to know" basis.
"I didn't want to be wrongfully or inadvertently implicated in any military witch hunts for 'moles' -- secret agents planted by the enemy within organizations to leak information. Of course, the military did throw us a few bones of information to keep us motivated in our work during the war," says Dunwell.
For example, spies would relay to German U-boats coded messages containing the names, manifests, and departure schedules of ships from harbors around the world. The Allies used this information to alter shipping routes at the last minute.
As the Pacific war neared its end, Dunwell's code-breakers also learned that Japanese leaders approached Russian leader Josef Stalin with a peace plan that would safeguard the emperor and members of the royal family. Stalin rebuffed a diplomat seeking help in ending the war against Japan.
"We also learned of one Japanese plan to send take radio messages from the Aleutian Islands after they had been abandoned, in an effort to forestall an invasion by U.S. forces," says Dunwell. "Much of this cat-and-mouse activity was pure psychology."
"Only now, as the NSA itself reveals what transpired 50 years ago to the press and public, am I revealing this story," says Dunwell. "And even now, I'm restricting comment to old technology and some anecdotal information. I still would not reveal cryptographic principles, which are timeless and could be used by intelligence-gathering agencies."
By 1946, Dunwell's punch card work was reintroduced back into the IBM "Future Demands Department," and adapted into IBM's first electronic calculator, the experimental 603 Electronic Multiplier. Dunwell was honorably discharged from the Army, which awarded him the Legion of Merit, and went on to develop IBM's powerful STRETCH computer (the forerunner of the System/360, introduced in the l960s), for which he received an IBM fellowship, IBM's highest engineering award.
Today, Dunwell owns and manages Data Center Computer Services, a Poughkeepsie, N.Y., company and is cooperating globally with scientists, including members of the former U.S.S.R. Academy of Science, to develop a universal computer language that can be utilized across disparate computer networks.