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Britian's Secret


Computers in 1937?

Britainís Best Kept Secret

By Lynn L. Kauer

In September of 1998 Crystal and I shared some vacation time in Florida, with her sister (Yvonne) and husband (Brian) from Oxford, England. We met with them, and their friends (John and Janet) who were also traveling with them. During the week we spent with them I learned that John was involved with a British Historical organization on the task of rebuilding a computer.

While I didnít understand too much about what he was doing I did learn that one problem he had encountered was obtaining the proper screws with which to rebuild the machine. To make a long story short, via e-mail I was able to obtain a list of the screws he needed (15,000 of them) so I could take them with us to England when we went on vacation.

During our stay in England I had the opportunity to tour the site where the machine was being rebuilt. As always, the story behind the story I will be sharing is the more fascinating. It begins in 1935.

During 1935 Hitlerís forces began to encode their messages with a machine called the "Enigma." It wasnít a top secret machine because someone had attempted to market it for encoding banking transactions years earlier. At the time, there were over 1,000 of the devices on the market but the banks were not interested. However, Hitler was!

The machine looks a bit like a manual typewriter. The encoding feature was accomplished via three wheels with five positive and negative positions to determine the characters the machine would type. It worked as follows:

If the user set the first wheel to the Ďpositive 5í position, the second wheel to the Ďminus 3í position, the third wheel to the Ďpositive 2í position and typed the word "and" it would result in the word "ekf."

What happened is that when the "a" key was entered the letter five characters beyond (positive) would be used. The next key would select the second letter to the left of its preset position and so forth. This three-wheel combination was considered to be so secure as it offered tens of thousands of possibilities. Each night at midnight, Hitlerís forces changed the wheel combinations, which resulted in a new encoding procedure.

Mathematical probability dictated that it would take 1,000 people working independently nine lifetimes to break the code. As the code was being changed on a daily basis, and sometimes twice the same day, the encoding procedure was considered to be very secure.

Poland began to intercept radio transmitted messages being sent from Germany to other countries. It occurred to them that Germany might be up to something so they began to monitor the messages. After a short time, the messages began to be transmitted in an encoded fashion. A couple of their mathematicians learned how to interpret the code, translated the messages and learned of Hitlerís plans for invasion of neighboring countries.


A Computer is Born

One night three of the Polish mathematicians were eating ice cream and trying to figure out a way to automate a decoding process. After a while one of them did. They made a simple mockup of the decoding machine and were thrilled that it worked. They code named the device "Bomba" because it was the new flavor of ice cream they had been eating the night they developed the idea for the machine.


Fighting On An Allied Front

In 1937 these scientists invited British and French security specialists to a secret conference to inform them of what Hitler was up to. At first the British and French didnít believe them. When the Polish scientists showed them the broken encoded messages they asked them how they had broken the code. They answered their question by simply handing over to them the simple machine they had developed.

They knew Poland would soon be invaded and a captive of Germany. Their intent was to give a tool to someone who could work to free them in the future. The other problem was, a fourth wheel was added to the Enigma encoding machine, making the decoding process far more complex.

The machine was taken to England and the British Government "assumed ownership" of a private residence of a large landowner near London at a site known as Bletchley Park. It became the headquarters, and location, for 12,000 men and women working on code breaking. They are considered to be the single element that ended WWII two years early, saving thousands of lives.


The Bombe is Developed

Using the principles passed along from the Poles, a new machine was quickly developed. Out of respect for the Poles, the name for the new machine kept the same name except for the changing of the last letter.

As learned from a recovered photo, the machine is about eight feet in length and about six feet high. There are three banks of cylinders each three high with a combination of 12 and 13 cylinders in a row. On the ends of each cylinder are ten notches, five for positive positions and five for negative positions.

When a newly encoded message is captured, it is coded into the machine. Once entered the cylinders are turned notch by notch via a series of hydraulic pumps and lines. As soon as a message can be read (in German) it reveals the position code of the Enigma encoding machine for the three wheels in the encoding device. The code is then broken.

Once the start positions are known, they were set in a captured Enigma encoder, the encoded message entered, and the decoded message was translated by the Enigma. (Submarine Enigmaís used four wheels.)

What amazed me was that British intelligence would capture an encoded message, transmitted by radio, enter it into the Bombe and three to five hours later have the information to be able to decipher Hitlerís messages for the rest of the day. (The U.S. also had a similar machine with four vertical banks of cylinders. There was a photo of it at the park.)


Tour Notes

On the day I visited the site there was a tour open to the public. I learned that the code-breaking site was kept secret until twenty years ago. Obviously, the persons conducting the tours were quite proud of the accomplishments achieved at the site. One story was the occasion when a message being sent to Rommel in Africa was broken at 3:00am, translated and sent to Montgomery by 3:30am. Rommel got the same message at 6:30am, three hours after Montgomery had received it.

Submarine locations were found by interpreting messages that were sent to wolf packs. In order to maintain a veil of secrecy, a group of 20 to 40 spotter planes would be sent in random flight patterns. (Hitler had his spies in England also. If it became obvious that the plane would fly directly to the submarine, the cat would be out of the bag.) Only one of the planes was sent in the direction to find the submarine,-but the pilots of the planes didnít know this. Each felt they were really trying to find the enemy.

The pilots never understood why the military wanted the subs they found to see them and to know they were spotted. They would have preferred the subs to be attacked by surprise. Now itís obvious that in the interest of keeping Hitler from learning that all of his top-secret messages were being broken, the game was played to the fullest. On other occasions, flights of bombers were sent (and most shot down) to bomb factories that were known to be vacated by the Germans.


Colossus is Born

In 1939, the worldís first large electronic valve computer was developed that further speeded up the process of breaking and interpreting Hitlerís messages to his Generals. Itís about thirty feet in length, has hundreds of vacuum tubes, and a streaming paper tape punched with a series of holes that has a beam of light passing through them. It accomplishes the similar task of turning the cylinders of the Bombe computer.



When the war was over, Churchill ordered all of the Bombeís and the Colossus computer to be destroyed. One reason was no to give the technology to the allies, especially the U.S. who he feared would use it to advance technologically. Thus all machines and drawings were destroyed except for one set of drawings.

About 15 years ago, a warehouse was being cleaned. When a found crate was opened the drawings for the Bombe computer was found and the restoration process began. No drawings of the Colossis were ever found. However, the person who originally worked on the development of it rebuilt it from memory. Itís the working model on display today at Bletchley Park.

After the tour, I was somewhat in awe of the effectiveness of simple technology. Until now, I was under the understanding that computers were developed in the 50ís. How many of us know that the breakthrough came as a result of some Polish Mathematicians eating ice cream in 1937?

I also couldnít help but wonder if the "marketing hype" of Symantec and others, toward how secure their encryption software is, may not be in error. Maybe we havenít progressed as far as we might like to think.


copyright © 2000, Lynn L. Kauer

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Last modified:    April 2013