Quality History Tea: Code Girls

I don't know about you, but my history classes went a lot like so there was a war, here's why said war happened and all you need to really know is that we won. When I heard of the book Code Girls, and read a little snippet of it online - y'know the ones where the book first comes out and they're promo'ing it and it's getting hyped up in the tech community & CNN is like HEY BOOK BOOK BOOK. I was extremely interested for one reason: As a computer science major, there aren't many females in my classes. Hearing the words female and coders in the same sentence and followed by one another had me ready to toss whatever amount of money it cost on the counter of Barnes and Nobles to purchase this book.

Then again, I'm a university student so my local library was where I was headed. They had the book thankfully! However, since it was a new book, I had 14 days to read it. I'm a fast reader but that was a pretty chunky book to finish in 14 days so best believe I was taking advantage of renewing it every time I could.

For this book, I spent half the time reading a page and the other half pausing midway to look at my USA map to figure out what the distance was between two states - this mainly pertained to inner USA, clearly my USA geography knowledge that I didn't have was slowly becoming something I did have by the end of this book.

Now, when I think of women during WWII, I just thought of nurses, mechanics and that's pretty much it. If you also have the same flow of thoughts of what women were doing during WWII, DO I HAVE SOME QUALITY TEA FOR YOU.


Well, for starters they weren't just nurses and mechanics. They were coders. Now, how did they become coders? Did Army/Navy officers just waltz in a cafe and say HEY WE NEED CODERS TO LOOK AT OUR ENEMY'S CODING TO FIGURE OUT WHAT THEY'RE SAYING? Uh no. NO. there goes national security if that actually did happen. 

At the time, education for women wasn't something parents thought was important since most places of work only employed men - the only profession women weren't turned away from was teaching. Since men were being shipped out to war after Pearl Harbor, women became the only option to recruit - that and men didn't want to be behind a desk.

 So, Army and Navy Officers looked at women colleges and asked the President/Headmaster of each university who they could recommend and began sending notices to young women at the university - however they weren't told up front that they were going to be breaking enemy codes- they walked in on their first day thinking they were going to be secretaries.

Now, all of these coders were not officially part of the Army and Navy but worked as civilians until 1942. For the women in the Navy, they were referred to as WAVES - Women Accepted for Volunteer Emergency Service.


Fun fact: I am currently in a WAVE program for girls and it's all about getting females majoring in Computer Science advisors to help them through their tech journey!

So as of now I have an advisor and it's great - I'm learning a lot!

The women focused on the Nazi's code and cipher and got to work on deciphering and decoding the communications. Breaking the ciphers and codes required for them to be able to spot patterns. English teachers and librarians were great at spotting patterns because they knew which letters and words were the most commonly used.

What is a code?

For example:

Cavalry --> HUNUG
Wagon Company --> DIGUF

You know how we text OMG instead of Oh My God - like that!

The codes would then be compiled and kept in codebooks - similar to dictionaries. You know way back in the day when people had dictionaries in their homes - I still have one - where you want to find a definition of a word. Think of it as looking up a word and instead of there being a definition, there's a code group.

That code group would be what the encoder (person writing said coding message) would write in their letter.

But here's where coding can get easy for code breakers to break into without a codebook - if there are constant repetitions of code groups then it makes it easier for the enemy looking in to crack the whole code apart.

What is a Cipher?

For example:

b --> X
r --> T
a--> V
i--> O
n--> P

Then the word brain --> XTVOP

Now that we have those differences covered, I wanted to discuss one part of the book - I could sit here and write about the whole book because it was honestly amazing to read so much history that I hadn't learned in my U.S. History courses but also disappointing to read something that I honestly believe should have been taught in history classes. DO YOU KNOW HOW HYPED AND EXCITED 14 YEAR OLD ME WOULD BE ABOUT LEARNING ABOUT WOMEN CODERS WHO CRACKED THE GERMAN'S CODE AND CIPHER? I would have shown up to history class early just to keep learning about them.

ALSO WAIT - If you think only America had women coders do I have some new tea for you: Thousands of British Women worked at Bletchley Park aka home for England's codebreaking unit. They worked on Bombe machines which deciphered the German Enigma. I have yet to read a book focusing on those thousand women, it seems I have more history to read!

So let's talk about the Battle of Normandy. The major key factor that allowed for this to be successful for the allies was dummy traffic (fake radio traffic that resembled real American traffic) created by women coders. Since they studied the communication of the U.S. military they were able to know what type of traffic to create and what should be said to make it believable for the enemy. They also analyzed the communications of Allies to create a fake believable version of that as well. 

For the Battle of Normandy, the goal was for the coders to convince the enemy that ~fictitious~ military units existed and were on their way to Strait Dover, toward the Pas de Calais. This ~fictitious~ military unit had a landing-craft tank, headquarters, and two assault forces with associated ships and craft. A few months before the D-Day landing, the dummy traffic had this ~fictitious~ army traveling around England.

And did the deception work? YA BET IT DID.

An encrypted message from Hitler confirmed that the Nazis expected this ~fictitious~ army to land in Norway and Denmark and on the French Mediterranean coast.

Now where was the REAL Allies army going?

Normandy, France.

When the Allies arrived in Normandy, France the Nazis were like HOLD UP WHAT - they were caught by surprise because based on the ~fictitious~ army communication the Allies were headed to  Pas de Calais (the narrowest part between Britain and France).

The women coders creating the communication for the fictitious army and deceiving the Nazis saved about 16,500 Allied lives.

To learn more about D-Day, you can read: D-Day - World War II 


After I finished reading Code Girls, and learned about ciphers and codes, I thought to myself why not code an ~unbreakable~ code & cipher? And that's when I got my mini notepad out - I prefer to sketch what I want to do by hand before opening up my software to begin coding away - and got to work.

I decided I wanted to use a cipher for each individual letter and code groups for words/phrases. Now, how does one make an ~unbreakable~ code & cipher? RESEARCH THE CODES AND CIPHERS OF THE PAST. To see the flow of how a cipher and code was supposed to work and look, I found myself looking at Telegraph Codes. WAY back in the day, cable companies charged per word sent so there were public codes that helped saved people a lot of money. Instead of being charged for the phrase I don't understand what you're saying, you'd look at the public codebook and see that phrase is represented by the code group HJNAL.

I then found myself looking at Australian Railway Telegraphic Codes and Great Western Railway Telegraphic Codes to see how code groups looked depending on the setting they are used in. 

It took me about a month to complete this fun side project and it is honestly my literal pride and joy. To think, I wouldn't have created this project if I hadn't read the book Code Girls and learned how important codes and ciphers were and how code breakers - namely female code breakers- shortened the length of the war because they deciphered and decoded the enemy's communication.

that moment where your own code has the AUDACITY to not work because of a missed semicolon on line 1516;


I'm being honest when I say I was chatting to a friend of mine and sent her the link to it and I didn't hear from her for a bit and it turns out she was having way to much fun with my coding system I created! 

The art of writing or solving codes.

HAVE FUN! I'd love to know what you guys think of it; it was really fun to code and challenge myself!

me sipping my high quality chai tea latte and side-eyeing my code that didn't like me .5 seconds ago 

If you'd like to see more about my thought process for my codebook: Behind the Codebook



  1. This is such an interesting post! The book isn’t something I’d personally ever think to pick up and I don’t think I’d be able to read into it in so much depth so I’ve really enjoyed learning a little about it through your summary!- https://sophiehearts.net x

    1. Thank you!! In the beginning it was a bit hard to get into the book seeing as I had to look at a map every few seconds to see the distance between two states but I slowly got used to it and found some sort of rhythm while reading (if that makes sense)! I'm so glad to hear you enjoyed reading this post, it was really fun to learn more about history and to write a small summary on part of the book! :)