# World War II - The Enigma Codes and the Master Code Breakers

Updated on March 10, 2013

## Deciphering the Enigma Codes

Deciphering codes is a fascinating activity that has captivated people for thousands of years.

I have a special personal interest in this because as a young child I had an indirect contact with this activity due to my father’s work in counter-espionage during his years as a staff member of the British Embassy in Santiago, Chile. (See my article on Allied Counter Espionage).

Now, quite some years later, I still find it fascinating and the history of the German Enigma Codes can be really absorbing!

## Basic Cipher Systems

The objective of all cipher systems is to make the deciphering of an intercepted coded message as difficult as possible.

To this purpose, is it is important to make the message key as secure as possible, and that the recipient is familiar with the specific message key that has been used.

Another important factor is that the cipher system used should be able to count on an enormous number of possible message keys, that is different ways in which the message could have been coded, otherwise an interceptor can “break” the code by simply trying out various alternatives, and if these are only a few, is sure to eventually strike it lucky.

## Substitution Ciphers

The Enigma codes are very sophisticated substitution ciphers. A cipher of this type involves substituting one letter for another according to some rule.

A very simple substitution cipher is created by listing the letters of the alphabet consecutively and then placing another row under the first, with the letters displaced to the right. Let’s say we displace the second alphabet 5 places to the right.

In this way, the letter E would be replaced by the letter A.

To be able to decipher any message, the recipient would have to know the rule and the message key.

Ciphers such as these are easily broken, when combined with other details, such as knowing the most common letters of a language, which in the case of the English language is the letter (E); or the list of most common words of which the percentage of occurrence is known. The first ten most common words in English are: THE OF AND TO A IN THAT IS WAS HE and the frequency percentages for these words have already been calculated.

## A Simple Substitution Cipher

A
B
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E
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N
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Q
R
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T
U
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W
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A
B
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E
F
G
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I
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N
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This shows why the letter E would become the letter A in this simple cipher

## The Enigma Cipher

The Enigma is a very sophisticated substitution cipher, of the type known as a poly-alphabetic system. In this case, there is more than one substitution alphabet, and the various alphabets are constantly rotated or altered according to some rule.

When using the poly-alphabetic systems, the message key has to include the total system, that is the alphabets used and the rule for using them. If the encoding is then done by hand it requires a large handbook and hours of work.

The problem of the time consumed and the risk of errors when working with these poly-alphabetic systems lead to the invention of electro-mechanical rotor cipher machines, of which the most famous was the Enigma.

The basic Enigma machine and encoding process was invented in 1918 by Arthur Scherbius, a German. The machine was originally devised to be used by commercial companies interested in maintaining their communications as private as possible.

Between 1925 and 1933, the German Navy, the German Army and the Luftwaffe had all adopted various versions of the Enigma machine.

## France, Britain and Poland share initial facts on the Enigma

In 1931, the dangers posed by this equipment came to the attention of France and Britain, but they were unable to make any progress in breaking the codes used by the Enigma.

The Poles were also worried about decoding the Enigma, as they felt threatened by Germany’s increase in military power. In order to discover the intentions of the Germans and the Russians that surrounded them, the Poles stepped up their intelligence gathering efforts and also their efforts at code breaking.

The intercepted radio transmissions from Germany showed that a new cipher system was in use, eventually identified as the Enigma. The Poles were familiar with the commercial Enigma machines, but were unable to break the military codes. Their stroke of genius was to try a mathematical approach, for which they formed a team of notable mathematicians, amongst whom were Jerzy Rozycki, Henrtyk Zygalski and Marian Rejewski.

However, the Enigma was no ordinary machine. It used the combined workings of several wheels that carried the letters of the alphabet on their rims and were wired together in a complex way. This raised the possible alternatives for letter substitutions to a degree that was unknown at that time.

For instance, in a three wheeled Enigma, the operator could press the letter A on the keyboard, and this would connect through the first wheel to the second wheel, where it was substituted. Then the wiring took the signal to the third wheel, where the letter underwent another substitution. Then that letter was switched with yet another change, and then followed the wiring back to the first wheel along yet another route, where a lamp lit up on the keyboard to show the corresponding substitution letter, perhaps a T.

During all this process, the first wheel would step up one position after pressing the initial A key, so that the next time A was pressed, the route would produce a different final letter, maybe an N. All this during the same message, mind you!

## The Polish Cryptographers Make Progress on the Enigma Codes

After World War II started, the Germans improved their machines yet again, enabling the operator to decide on the initial positions by hand setting the position of the wheels within certain parameters, according to the code books for that weekly or monthly period.

The Poles had access to some information about the Enigma, from the French cryptographer Gustave Bertrand, who in turn obtained some partial information from a German spy. As the French efforts were unsuccessful, this information was shared with the British and finally with the Poles. Rejewski was then able to deduce the pattern for the internal wiring and so was able to advance a little further. The Polish team devised a set of perforated sheets set out in a grill formation. These sheets carried letters for every perforation and were placed one on top of the other following complex patterns provided by mathematical calculations for combinations and permutations. When the deciphering team scored a hit, the light under the sheets shone through a specific set of superimposed perforations and that enabled the team to “read” the path followed by the wiring in that particular message, and so on to the decoding.

## Rejewski's Bomba (or Bombe)

From the use of these perforated sheets, Rejewski designed a mechanical method for finding the Enigma settings at any given time. The Bomba was like a rudimentary computer, a sort of wall stand covered in notched wheels.

The Germans kept introducing more complex workings to their Enigma machines. Just before the start of the war, the German Enigma acquired a total of five wheels, of which the operator chose three when encoding his message. This again raised the number of possible permutations, and the Poles were unable to keep up within their limited resources.

In July 1939, with the threat of invasion coming closer every day, the Polish team decided to share their results with the French and the British in a secret meeting. Just before the German invasion, the three principal Polish code breakers made their escape from Poland to safety.

## Britain's Bletchley Park

Bletchley Park is an estate located in Buckinghamshire, England, which currently houses the National Codes Centre and the National Museum of Computing.

During World War 2, Bletchley Park was the main decryption establishment of Britain´s effort at deciphering the codes of the Axis forces. By far the largest efforts involved the German Enigma ciphers.

Cryptanalysts were selected for various intellectual achievements and skills, whether they were linguists, chess champions, crossword experts, polyglots or great mathematicians. The intelligence produced from decrypts at Bletchley was code-named “Ultra”.

Alan Turing was without doubt the most famous (and eccentric) mathematician at Bletchley Park. He is now known as the father of modern computing, based on his work on the refined model of the Polish Bombe that allowed the cryptographers at Bletchley to finally break the Enigma codes.

## The Work Carried Out at Bletchley

The initial British Bombe was produced by Turing in 1939 at Bletchley, and later improved in 1940 by Gordon Welchman. The engineering design and construction was the work of Harold Keen.

When the United States entered the war, British and American leaders agreed to pool resources. A number of American cryptographers were posted to Bletchley Park and were inducted and then integrated into the Ultra structure. This cooperation soon extended to all British and American military intelligence organizations.

Later the initial staff would be joined by thousands of WRNS (WRENS) and other technical personnel, who were billeted in surrounding properties.

The information provided by Ultra contributed greatly to Allied success in defeating the U-Boats in the Battle of the Atlantic, and to British naval victories in the Mediterranean. In 1941, Ultra exerted a powerful effect on the North African desert campaign against the German army, under General Erwin Rommel. Prior to the Normandy landings in June 1944, the Allies knew the locations of all but two of the 58 German divisions on the Western front.

Churchill is said to have referred to the Bletchley staff as "The geese that laid the golden eggs and never cackled".

A major setback was caused by the German Navy introducing the four rotor Enigma used for communicating with U-boats. This change temporarily stopped the ability to read this network from February to December 1942.

Of particular importance to the work at Bletchley were the Enigma machines and codes captured by boarding defeated U-boats.

## The Case of U-110

A great breakthrough for the efforts of the teams at Bletchley happened in May 1941 with the capture of an intact Enigma machine from U-boat 110.

The U-boat had been forced to surface after depth charging and the inexperienced crew abandoned ship believing that the U-boat was sinking. They had obviously abandoned in great haste, leaving books and gear all over the place. The British boarders formed a chain of men to pass up all books and charts that looked even remotely interesting.

Every boarding party was under orders to include a telegraphist and there was no exception for U-110. In this case the boarding telegraphist found the W/T office in perfect condition, with all books and apparatus intact. The coding machine was still plugged in as though it was in actual use when abandoned. It looked like a typewriter, but at the same time had some strange features, so the boarding crew decided to take it with them. They knew nothing of the top secret Ultra, so they did not know how extremely important this decision was!

## The Documents Recovered from U-559

On 30th October 1942 radar contact was made on a U Boat by a Sunderland flying boat on patrol in the Eastern Mediterranean. The Allied destroyers that were alerted arrived in the vicinity and proceeded to attack the U-boat (U-559) with depth charges.

Eventually the U Boat was forced to the surface and its crew abandoned ship. Three crewmen from HMS Petard then carried out a risky boarding of the damaged submarine. They were First Lieutenant Anthony Fasson, Able Seaman Grazier and Tommy Brown, a young lad from the canteen.

They were able to save some secret looking documents which were passed along. Fasson and Grazier then went back down to try to recover some electronic equipment and while they were down the U Boat suddenly started to sink. Tommy Brown jumped clear but Fasson and Grazier were drowned.

The documents arrived in Bletchley Park on 24th November 1942. There they were identified as Enigma code books and were considered vital to removing the block that had occurred in the deciphering attempts after the German Navy had introduced the 4 wheel Enigma machine.

Fasson and Grazier were awarded posthumous George Crosses, and Tommy Brown also received a medal.

## Bletchley Park Today

The days of secrecy have fortunately long gone. Bletchley was abandoned for several years and fell into disrepair, but now there are serious efforts under way to recuperate the installations. The place is in the hands of the Bletchley Park Trust, and is now a heritage site and a museum where the various exhibitions allow visitors to understand the fascinating story of what went on there!

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• AUTHOR

Joan Veronica Robertson

5 years ago from Concepcion, Chile

Hey handyman I've just seen this, many thanks!

• Bill

5 years ago from Greensburg Pennsylvania

Here is the link to it. http://www.knoxnews.com/news/local-news/knox-world... as requested.

• AUTHOR

Joan Veronica Robertson

5 years ago from Concepcion, Chile

How very interesting! How can I read that article? Please comment here with more details, this is so fascinating!

• Bill

5 years ago from Greensburg Pennsylvania

I had an Aunt that work as a wave during WWII. She was involved in the code breaking effort and work in Washington D.C. during the war. She is 94. There was an article written about her. She lives in Knoxville TN.

• AUTHOR

Joan Veronica Robertson

6 years ago from Concepcion, Chile

Hi JayeWisdom so happy to read your comment! Isn't this a fascinating topic? I find it so interesting, especially as my Dad served in counter-espionage in Chile during WW2 and was involved in the use of codes.

On my profile you would find some more posts on WW2, all with a sort of personal twist. You might like to read them too. Thanks again!

• Jaye Denman

6 years ago from Deep South, USA

Fabulous hub, Joan, and timely since I recently watched the UK mini-series "Bletchley Circle." The breaking of enemy codes in World War II was certainly a vital contributor to Allied Forces' victory. I didn't know about the Enigma machines, so read every word with fascination and enjoyment. You are a superb WWII chronicler.

Voted Up++

Jaye

• AUTHOR

Joan Veronica Robertson

6 years ago from Concepcion, Chile

Hi Vellur thanks very much for reading and commenting. I'm happy you liked the Hub. See you!

• AUTHOR

Joan Veronica Robertson

6 years ago from Concepcion, Chile

Hi Daisy Mariposa many thanks for your continuing support! This was a lovely comment to read, and thanks also for the shares. I hope to see you again soon!

• Nithya Venkat

6 years ago from Dubai

Very interesting and informative hub about Enigma Codes and Master Code Breakers. Thank you for sharing this well researched hub with us. Great write, voted up.

• Daisy Mariposa

6 years ago from Orange County (Southern California)

Joan,

What a well-written well-researched fascinating article! I enjoyed reading it very much. I will be tweeting it and sharing it with my HP followers.

• AUTHOR

Joan Veronica Robertson

6 years ago from Concepcion, Chile

Hey! So happy to have you visit and many thanks for the comment! I'm glad you liked the post, it's one of my favorites. See you!

• David Paul Wagner

6 years ago from Sydney, Australia

A fascinating historical story well told. Your clear and large-sized images really add to the presentation too. Thank you, Joan.

• AUTHOR

Joan Veronica Robertson

6 years ago from Concepcion, Chile

Hi Chitrangada Sharan I'm so glad you found this information to be of value to you. I do try to provide the very best I can manage, because the events do merit that effort. Thanks for the comment and I'll see you soon.

• AUTHOR

Joan Veronica Robertson

6 years ago from Concepcion, Chile

Hey vocalcoach many thanks for your comment and the share! Your support is so valuable! I'll be seing you soon.

6 years ago from New Delhi, India

Very interesting and informative hub!

I came to know a lot of history through you're such engaging and well researched hub!

• Audrey Hunt

6 years ago from Idyllwild Ca.

I so enjoyed this. I love your writing! Sharing.

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi there, Teresa, many thanks for your visit and comment. I'm really happy you enjoyed this Hub! See uou.

• Teresa Coppens

7 years ago from Ontario, Canada

Amazing hub. Kept me engaged from beginning to end. Well done!

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi Claudio, so happy to have you visit my Hub! I'm glad you liked it, it IS a fascinating topic! Have a good day!

• Claudio Müller

7 years ago

Fascinating article. Thanks for sharing your knowledge and experience with us.

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi Mary, I feel so honored to have received your comment. You are one of my model writers on Hubpages, so this is of great value to me! I've been a teacher for most of my (long) life, so it's kind of natural for me adopt this mode, and I think that's what guides the way I structure my Hubs. I don't write it unless things fall into place so that I can make the ideas clear to those who read the Hub. It all comes from being a Math teacher, there has to be a sort of sequence! I'm glad these thought processes are surfacing when I work on a Hub, but it's slow work! Thank you once again, and have a good day!

• Mary Craig

7 years ago from New York

You are the best history teacher ever! I had no idea there were "machines" to decipher code...how very interesting your life has been and how lucky we are you choose to share it here. This hub was interesting from beginning to end and you chose such beautiful pictures. Thank you for again educating us on the past in a way we can enjoy!

Voted up, useful, and interesting.

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi Paul, thanks so much for the visit and the comment! The problems of the decoding efforts in WW2 and of counter-intelligence have been part of my life since I was a child, as my Dad worked in counter-espionage in Chile during WW2. The anecdotes I remember from childhood are related in two Hubs that precede this particular one, but all in all this was a fascinating period! I'm so glad you liked the Hub, it was difficult to decide what to include and what to leave out, there is such a lot to write about! I hope to see you around!

• Paul Maplesden

7 years ago from Asheville, NC

This is a fabulous hub - I love the way that you've used illustrations and great photos to perfectly illustarte your points; fantastic work.

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi rasta, many thanks for th visit and the comment, I'm glad you liked this Hub, I enjoyed writing it! The topic is so fascinating, and ther is so much information now about what usedt to be Top Secret. Thanks again and have a good day!

• Marvin Parke

7 years ago from Jamaica

Very detailed information . I enjoyed it very much.

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi midget, so happy to see your comment! I agree, this era is fascinating, I've been reading it up all my life! I will defiitely keep on writing about it! Thanks for this motivating visit and the share! Have a good day!

• Michelle Liew

7 years ago from Singapore

Fascinating account of the techniques used viz The Enigma. This era has always been a fascinating one and please keep them coming!! Sharing!!

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi teaches, so happy to receive your visit and your comment! You are very supportive, as always! It gets lonely sometimes around where I am, so far away, so I find the Internet is a wonderful place to communicate. I'm glad you liked this Hub, the topic has always fascinated me also! Best of wishes and have a good day!

• Dianna Mendez

7 years ago

Very impressive post, as usual, Joan. I have seen a movie or two about this era and The Enigma always fascinates my hubby. Great coverage and education. Keep them coming!

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi, bd, Your visit and comment are very welcome! I agree, it is a fascinating story! It's also a part of quite a long series in similar topics, maybe you would also enjoy some of the other Hubs in that group? Anyway, thank you for the visit and the comment, this is a good start for my day (it's 6.00 am here!) Have a good day!

• Bill De Giulio

7 years ago from Massachusetts

Joan, what a history lesson. This was amazing. The stories of the U-boats had wanting to read more and more. Thank you for a fascinating look at an important part of WWII history.

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi ps, many thanks for your visit and the comment! I'm so glad you enjoyed this Hub, and I do hope you will also enjoy the two previous ones I have written about Allied counter-espionage and my Dad's activities. Your comment is very valuable to me, so thanks again! All the best from far away Chile!

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi farmloft! Your comment is quite the most extraordinary I have received while writing on Hubpages! I would never have thought of looking up our friend Tommy! You have taught me a new venue for ideas! Thank you! I really had collected so much information on the Enigma, I had some trouble cutting it down! Your visit and comment are greatly valued! Have a good day, (or evening, or night, I never really know!)

• Patricia Scott

7 years ago from North Central Florida

This is amazing. So much information that is of interest. I learned so much. How interesting it must have been to have a Father who was so closely tied to counter espionage.

Voted up ++

Sending Angels to you and yours..:) ps

• farmloft

7 years ago from Michigan

History is so often made up of ordinary people doing ordinary things that turn out to be extraordinary! You inspired me to look up whatever happened to Tommy Brown. Unbelievably: his heroism cost him his "job" because he was only 15 years old when he helped get those secret documents from the U Boat, too young to be in the service on a ship. Unfortunately his bravery cost even more, while he was on leave in 1945, he died trying to rescue his sister from a fire. He definitely was hero material.

According to The Northerner Blog referring to Tommy and his shipmates' discovery: The naval historian Ralph Erskine thinks that, without the breakthrough, the Normandy invasion would have been delayed by at least a year, and that between 500,000 and 750,000 tons of allied shipping were saved in December 1942 and January 1943 alone.

Thanks, Joan, voting up++

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi Billy! Your visits and your comments are so heartening! It gets lonely sometimes here in far away Chile, but with comments like yours, the blues all fade away! Thanks so much, and a good day to you!

• Bill Holland

7 years ago from Olympia, WA

you are amazing! Your hubs on history are among the best written on HP. I always learn tons of information....this is just a wonderful look at history. Thank you Joan!

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi Pavlo! Isn't it great to meet every so often on Hubpages? I'm happy for your visit, and your comments are always welcome! Have a good day, and thank you!

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi irish eyes! Isn't this topic fascinating? I spent hours reading about it and then found there was just too much information! Thanks for the visit and the comment! Your feedback is very welcome! Have a good day!

• AUTHOR

Joan Veronica Robertson

7 years ago from Concepcion, Chile

Hi, MG Singh, so nice to have you visit and comment! I'm glad you liked it! It took a lot of work to organize, but the result was worth it, I think!

7 years ago from Kyiv, Ukraine

Your hub is great! You reveal unknown pages of history. Thank you!

• Shining Irish Eyes

7 years ago from Upstate, New York

Joan - You KNOW I always enjoy your articles concerning WWII and this one held a particular interest as I have always been fascinated by this particular concept during the war.

Great write!

• MG Singh

7 years ago from UAE

This is very interesting. An captivating account. Good show and voted up

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