Recently in extension Maths, we have been researching cryptology and learning how to decipher various codes.
What is cryptology?
Simply put, cryptology is the study of codes. It can involve researching various ciphers and learning how to decipher and encrypt certain messages. Cryptography was used often throughout the World Wars as ways to communicate secretly to other people.
Win class, we were taught how to decipher many different types of codes and ciphers, such as Substitution Ciphers. A well-known cipher that we learnt about that falls under this category is the Caesar cipher, which is one of the earliest, yet simplest ciphers that is around nowadays. The way this cipher works is by replacing each letter of the top secret message with a different letter from the alphabet that is a certain number of letters away. For example, the a could be d and the b could be e etc.
Mrs H, our Maths teacher, also taught us how to encrypting various codes using the Vigenère Square as well. The Vigenère ciphers are known as polyalphabetic substitution cipher. The Vigenère Square is used to encrypt these ciphers as it has a series of alphabetic text (the whole alphabet) running in different sequences based off the Caesar cipher. Below is a picture of the Vigenère Square.
I have just listed two of the types of ciphers that we learnt about in Maths above, however there are many more that I encourage you to research as cryptology is an incredibly fun area of maths.
I have made some fun cryptography puzzles that you may want to try and complete. Please comment and let me know what you think the answers could possibly be and I will get back to you as soon as possible. I have made them using the Caesar cipher so they are easier to work out.
Tip: You can use a Vigenére Square (like the one above) to work this out.
Below is an example of how to work out a cipher.
How to work it out: Look for the letter that reoccurs the most. This letter is most likely e.
Assuming that h is e, place your finger on the e at the top of the square and run your finger down until you find h. Then circle the entire line that the h is on. Next find the letter w in the very same line and run your finger up to the top. You will notice that the letter is t. This is what you should have deciphered from the passage so far.
Then repeat the previous step for the rest of the letters.
The answer is test cipher.
Now that you know how to decipher various Caesar ciphers using the Vigenére Square, you can have a go at the following problems.
1. Below is a joke that I have encrypted:
X: Doha ohwwluz pm fvb lha flhza huk zovl wvspzo? H: Lclyf tvyupun fvb’ss ypzl huk zopul!
2. Below is the answer to the joke:
H: Lclyf tvyupun fvb’ss ypzl huk zopul!
That’s it for now, and if you have any further questions or you would like me to explain further on cryptology please leave a comment below.
Thank you for reading my post,