Lesson 2
Caesar cipher algorithms
Introduction
In this ‘unplugged’ lesson students create their own Caesar cipher, firstly using card before writing, testing and debugging algorithms to create a Caesar cipher to encrypt and decrypt messages.
Learning objectives
- To create and use a paper-based Caesar cipher to encrypt and decrypt messages
- To use logical reasoning to write algorithms to encrypt and decrypt messages using a Caesar cipher
- To test and debug algorithms effectively
You will need
Downloadable resources:
- Lesson plan
- Lesson slides
- Student handouts
Other resources:
Card, scissors, paper fasteners / split pins, paper - large sheets, pens
Quick links
Lessons created in partnership with Nominet
Lesson plan
Introduction: Recapping cryptography (5 minutes)
Creating card Caesar ciphers (20 minutes)
Caesar cipher algorithms: encryption (15 minutes)
Caesar cipher algorithms: decryption (10 minutes)
Review & wrap up (10 minutes)
Differentiation
Opportunities for assessment
This content is published under a Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) licence.