Caesar Cipher

The Caesar Cipher has a long history of usage, dating back to Julius Ceasar (100BC-44 BC). The cipher works by substituting for each letter the letter that is n letters further along the alphabet, where n is the key.

Skill: pattern and sequence, problem solving skill

Resources: Caesar Cipher template and worksheet (see below)

Activity: Give each student a copy of Caesar Cipher template, they need to cut it out, and fasten the two wheels together e.g. using a paper clip. Two extra wheels, at the bottom of the page, are for pupils to encode using numbers and also to create their own code.

As an introduction, you can begin with writing on the board: “Today we will be encoding secret messages” but backwards (similar to Leonardo Da Vinci’s but not mirror backwards). Ask your students to decipher that sentence and chat about other cipher methods that students may be familiar with.