Creating Your Own Code: The Super Secret Code

Learning Objectives Define 'encoding' and 'decoding' in the context of computer science. Explain why computers need to represent information using codes. Create a simple substitution cipher to encode a secret message. Decode a message that has been encoded using a given cipher key. Represent letters of the alphabet using numbers (e.g., A=1, B=2). Compare different encoding schemes and understand there can be many ways to represent the same information. Ever wanted to send a message that only your best friend can read? 🕵️‍♀️ Let's learn how computers do something similar every single day! In this lesson, you'll become a code-maker! We'll learn how to turn regular words into secret messages, a process called encoding. This is how computers s...

TermDefinitionExample DataInformation that can be collected and read by a computer.Your name, your age, or the letters in a word are all data. RepresentationA way of showing or storing information.The number '5' can be represented by the word 'five', five tally marks (|||||), or five dots (●●●●●). EncodingThe process of changing information from one form to another, usually into a special code.Encoding the letter 'A' as the number '1'. DecodingThe process of changing coded information back into its original, understandable form.Decoding the number '1' back into the letter 'A'. CipherA secret way of writing; a code. It's a set of rules used for encoding and decoding.A simple cipher could be 'replace every letter with the...

The Number-Alphabet Rule A=1, B=2, C=3, ..., Z=26 This is a simple and common way to encode letters. To encode a word, you replace each letter with its matching number based on its position in the alphabet. To decode, you replace each number with its matching letter. The Reverse-Alphabet Rule A=26, B=25, C=24, ..., Z=1 This is another encoding pattern, but it's backwards! It makes the code a little trickier. The key is that the alphabet is in reverse order when assigning numbers. The Keyword Shift Rule (Caesar Cipher) Pick a secret number (your key). To encode, shift each letter forward in the alphabet by that number. If your key is 3, 'A' becomes 'D', 'B' becomes 'E', and so on. If you get to the end of the alphabet, you...