Figure 1.--

American military codes proved to be the most secure system used in Wotrld war II. The Germans broke some codes before the United States entered the War. But at this time, a new code system was being introduced which Axis cryptologusts were unable to crack. The new American codes were never broken. Some authors have used the term 'unbreakable', but there is in reality no unbreakable system, primarily because people are involved. The Enigna machines, for example, were broken because the Brutish obtained actual machines and operators used sloppy procedures. The American code system was known as SIGABA which has been described as the most secure cryptographic machine used by any World War II beligerant. The U.S. Army developed the SIGABA system before the War. SIGABA looks like an acronym, especially the SIG which looks like signals. But in fact does not stand for anything. It is purely a code word. Army cryptologists completed the desigs for the basic machine (1935). It was similar in somecrespects to the German Enigma machine, but the output was emensely more complex. The Army shared the design with the Navy. The Army and Navy after field tests both adopted SIGABA (1940). The system was fully opperational (August 1941), but not fully deployed until after America entered the War (Early-1942). The military had deployed more than 10,000 SIGABA machines around the world (1943). As far as we know, neither the Germans or Japanese managed to capture one, but this has to be confirmed. We do not know to what extent the Germnans and Japanese or for that matter the Soviets tried to crack SIGABA. Unlike Enigma, SIGABA was never cracked. The SIGABA machines were linked with British machines to let Presidents Roosevelt and Truman communicate securely with British Prime Minister Churchill. The Germans were able to listen in to trans-Atlantic phone conversatiions even though they were scrambled. SIGABA messages, however, were secure. The Americans and British shared many secrets. One exception was SIGABA. The SIGABA system was so effective that it continued to be used by the Americans for more than a decade after the War. It was finally replaced when a faster communication system was required (1959). An interesting development during the War was the use of Navajo code talkers in the Pacific. The Germans did break the State Department's black code as well as descrabled trans-Atlantic telephone conversations.

Military Codes

American military codes proved to be the most secure system used in Wotrld war II. The Germans broke some codes before the United States entered the War. But at this time, a new code system was being developed and introduced a few moths after America entered the War. Germany’s Naval B-Dienst (Beobachtungsdienst - Surveillance Service) was reading a number of American encoded communications systems. The German Navy reading U.S. naval traffic enabled the U-Boats to achieve considerabe success in the second Paukenschlag (Operation Drumbeat). The new system was introduced (April 1942). Axis cryptologusts were unable to crack it. The new American codes were never broken. Some authors have used the term 'unbreakable', but there is in reality no unbreakable system, primarily because people are involved. The Enigna machines, for example, were broken because the Brutish obtained actual machines and operators used sloppy procedures. The American code system was known as SIGABA which has been described as the most secure cryptographic machine used by any World War II beligerant. The U.S. Army developed the SIGABA system before the War. SIGABA looks like an acronym, especially the SIG which looks like signals. But in fact does not stand for anything. It is purely a code word. Army cryptologists completed the desigs for the basic machine (1935). It was similar in somecrespects to the German Enigma machine, but the output was emensely more complex. The Army shared the design with the Navy. The Army and Navy after field tests both adopted SIGABA (1940). The system was fully opperational (August 1941), but not fully deployed until after America entered the War (Early-1942). The military had deployed more than 10,000 SIGABA machines around the world (1943). As far as we know, neither the Germans or Japanese managed to capture one, but this has to be confirmed. We do not know to what extent the Germnans and Japanese or for that matter the Soviets tried to crack SIGABA. Unlike Enigma, SIGABA was never cracked. The SIGABA machines were linked with British machines to let Presidents Roosevelt and Truman communicate securely with British Prime Minister Churchill. The Germans were able to listen in to trans-Atlantic phone conversatiions even though they were scrambled. SIGABA messages, however, were secure. The Americans and British shared many secrets. One exception was SIGABA. The SIGABA system was so effective that it continued to be used by the Americans for more than a decade after the War. It was finally replaced when a faster communication system was required (1959). An interesting development during the War was the use of Navajo code talkers in the Pacific.

Diplomatic Codes

The Germans did break the State Department's black code.

Trans-Atlantic Telephone Conversations

The Germans also managed to descramble trans-Atlantic telephone conversations. This included conversations between Prime-Ministr Churchill and President Roosevelt. The Deutsche Reichspost broke the scrambled voice transmission of the American-British transatlantic telephone system. German technical experts built a de-scrambling device and estanlished an operation in the Dutch town of Noordwijk wher they could get a good signal. Here they were routinely) listening to the higgly classified telephone conversations between Churchill and Roosevelt (1940/41). This continued until after D-Day and the Allies advanced into Belgium and the Netherlands (September 1944). The Germans had to relocate their telephone intercept facility. They moved to Bavaria, a poor choice because they could not het a good signal. This significantly impaired their interception efforts. This was a potentially dangerous achievement, but we donot know of any great insights gained by the Germans. Apparently the Allies were aware that their scrabling system was not scure and the high-level individuals involved were appropriately cautious when using the system.

Created: 4:25 AM 3/30/2011
Last updated: 2:55 PM 1/13/2018