A.4.15 Learning Goal
- Author:
- Katie Akesson
- I understand the meaning of “inverse function” and how it could be found.
- When given a linear function that represents a situation, I can use words and equations to describe the inverse function.
A Caesar shift cipher (or shift cipher) as a way to encrypt a message by shifting its alphabet position a certain number of places. The message in the warm-up is called "a shift of 3" because it substitutes each letter in the original message with the letter 3 places down. A table could be used as a key. It enables us to easily see the plain-text alphabet and the cipher-text alphabet. Here is an example for a shift of 3.
A similar table could be used as a key for a shift of 5, 2, -3, or any other number.
Another tool that can be used as a key for multiple shift cipher is a cipher wheel, as shown here.
The two alphabet circles are seperate, but layed on top one another and attached in the center with a pin so you can spin them to match up any shift.
Here is a picture of Ralphie from the movie "A Christmas Story" using A Cipher he got in the mail from Ovaltine to encode a message:
Today we will use the idea of writing and decoding a cypher to think about inverse functions.
A similar table could be used as a key for a shift of 5, 2, -3, or any other number.
Another tool that can be used as a key for multiple shift cipher is a cipher wheel, as shown here.
The two alphabet circles are seperate, but layed on top one another and attached in the center with a pin so you can spin them to match up any shift.
Here is a picture of Ralphie from the movie "A Christmas Story" using A Cipher he got in the mail from Ovaltine to encode a message:
Today we will use the idea of writing and decoding a cypher to think about inverse functions.