Mathalicious: Decoder Ring

What are some ways to encrypt secret messages?

Whether you’re a student passing notes in class or a spy trying to send a foreign communiqué, the ability to send a secret note is sometimes critical. But how are such secret messages created, and how can they be decoded when they reach their destination?

In this lesson, students learn about encrypting and decrypting messages using ciphers. After encrypting messages both graphically and algebraically, students try to decrypt some messages too. In the end, they’ll learn what makes for a useful cipher, and what makes a cipher impossible to decode.


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Math Topics
Algebra & Pre-Algebra, Cryptography
Middle School, High School
8th Grade, 9th Grade, 10th Grade, 11th Grade, 12th Grade

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