This Week’s Bonus – Learn to Use Ciphers

Is there a kid alive who hasn’t been captivated by secret codes and messages? Let’s be honest – ciphers and codes intrigue us all, from the truly young to those of us who are still young at heart.


We admit it. Over here at Brain Chase, we LOVE codes and ciphers. That’s why you’ll see them in all of our chases, in one form or another. And this week’s bonus challenge is no exception.  So, keep those Sunstone Medallions handy. Or, make sure you have access to our virtual Medallion. You’re going to need it!

Codes v. Ciphers

Aren’t codes and ciphers the same thing? Not exactly.

A cipher is a manipulation of individual letters using a series of mathematically-based steps. When facing a cipher, you would see a sequence of seemingly meaningless individual letters. But, if you know, mathematically, how each of the encrypted letters was created, you can work backwards and convert each to the intended message.

A code is a little less rigid than a cipher. Essentially, encoding is the process of taking a message and converting it into other words, characters, numbers, etc. Examples are Morse code and writing in short hand. And, of course, we have computer coding languages where by a series of commands are written which instruct the computer to carry out certain functions. Historically, codes have been used for brevity and to transfer confidential information and can be broken only when the sender and receiver understand the code.

The Vigenere & Caesar Ciphers

This week’s bonus challenge requires your student to interpret the Vigenere Cipher, which is a beefed-up version of the Caesar Cipher.

The Caesar Cipher is a very well-known, easy-to-break cipher. To create it, you simply shift the letters of an intended message a certain number of places to get a new number. So, if you wanted to encode the message “ABCD” by shifting the letters once left, you’d send your receiver a message of “ZABC.” The receiver would then have to shift the letters back one spot to find the original message. Below is an diagram of a simple Caesar Cipher with a left three shift.


The Vigenere Cipher takes this one step further. Each letter in the message is shifted a different number, based on a key word. To solve, you must use a Vigenere Square:


 If my original message were “ABCD” I would create a key word that is also four letters long, like, “HUNT.” To encode, I’d then use the chart.

To encode the A, I’d go the row with the first letter of my code word, H, and find the letter that is in the same column as the A. In this case, it would be “H.” For B, I would go to the row with the second letter of my code word, U, and find the letter in the B column, “V.” You’d repeat this process until you’ve completed transcribing the entire original message.

If your original message were very long, and your key word was “hunt.” You’d simply use the word hunt over and over again until you have encrypted every letter of the message.

FUN FACT: The Vigenere Cipher is actually named after the wrong man! To learn more about the history of the cipher, visit this website.

This week’s bonus challenge is even slightly tougher. Visit this webpage to get started! Good luck!

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