Cryptography: Sending Secret Messages

thingiverse

Students dive into cryptography by learning about the Caesar Cipher and the Vigene cipher. They put their knowledge to the test by encoding and decoding messages using a decoder ring that they create themselves. I designed this project from scratch. First, I opened the decoder ring model found here http://www.thingiverse.com/thing:14891 in Tinkercad. Then I added a rectangular prism and created a hole in the center so that the letters would be visible. Next, I turned the ring into a hollow cylinder and cut it away from the box [Figure 1]. After that, I removed the middle parts, leaving a small section on the bottom to hold everything in place [Figures 2 & 3]. Standards CCSS Overview and Background Project: Cryptography - Sending Secret Messages Students receive an introduction to cryptography. They learn two ciphers and practice encoding and decoding messages using a decoder ring that is 3D printed. By the end of this project, students will understand what cryptography is and have hands-on experience sending and receiving secret messages. They will also learn about the Caesar Cipher and the Vigene cipher and how to use them effectively. CCSS.Math.Practice.MP1: Make sense of problems and persevere in solving them. CCSS.Math.Practice.MP5: Use appropriate tools strategically. Lesson Plan and Activity Students are introduced to the Caesar Cipher, then they practice decoding a message. They think about why this cipher doesn't work well. Next, they learn the Vigene cipher and practice decoding another message. Students figure out how to use the decoder ring with the Vigene cipher. Finally, they encode a message and trade it with another group to decode their message. As an optional extension, students explore how these ciphers relate to modular arithmetic. Skills Learned Math.Practice.MP1 Math.Practice.MP5 Duration of Lesson This activity should take one day. Preparation No background is required for this project. For the extension, students should have a basic understanding of modular arithmetic. Rubric and Assessment Here is a sample rubric to use with the worksheet. Question (points) 1 (2) 2 (2) 3 (2) 4 (3) 5 (6) Total 15