Cryptography

This lesson is designed for 2nd Class, according to the Irish Education System.

Cryptography is the art of writing and solving codes, or "encrypting" and "decrypting". This lesson aims to teach students how to encrypt and decrypt messages using two different methods - the Caesar Cipher and the Pigpen Cipher.

Student's will use addition and subtraction to encrypt and decrypt the Casear Cipher. For later problems, Caesar Cipher wheels are needed. These are provided in print-out template form (split pins or cotter pins required), as well as an online Scratch version.

Two presentations are also available to aid teaching - one for the Caesar Cipher, and one for the Pigpen Cipher.

Cryptography History & Caesar Cipher


This powerpoint contains a brief introduction to cryptography and its history, and an example of the Caesar Cipher.

There is an option to view the presentation full screen by clicking in the bottom right corner.

Pigpen Cipher


This powerpoint focuses on the Pigpen Cipher.

It contains a brief overview and an example.

There is an option to view the presentation full screen by clicking in the bottom right corner.

Lesson Plan


A description of this lesson for teachers. Includes examples, timings, links to the curriculum, and much more.

View Lesson Plan

Student Booklet


A premade question booklet for students. Available both in a booklet template (only folding neccesary), as well as a full page option.

View Booklet Template

View Full Pages

Caesar Cipher Wheels


Available to be printed and cut out by students. Split pins required. Online version also available below.

View Template

Computational Tools



Caesar Cipher Wheel

Press the green flag to begin. Enter the shift required. The inner red wheel will spin to the correct position.

Remember, the inner red wheel is the encrypted letter, the outer black wheel is the decrypted letter!

Press the space bar to enter a new shift.

If at any point you need to reset this tool, press the green flag.

Caesar Cipher Encryptor/Decryptor

This tool is designed to encrypt and/or decrypt any message using the Caesar Cipher! You can use it to check answers, set questions, and more.

Press the green flag to begin. Select either the green or red button, depending on whether you want to encrypt or decrypt a message. You will then be asked for the message, and the shift. The teacher will then tell you what the answer is!

If at any point you need to reset this tool, press the green flag.

Game: Caesar Cipher Mission

This game is designed for students to practice decrypting the Caesar Cipher.

Can you use your new cryptography skills to complete this mission and catch the notorious Blackthorn Bandits?

Press the green flag to start.

To play this game on the Scratch website, and have the option of playing in full screen, click here.

Game: Taco Bandits - Pigpen Cipher

This game is designed for students to practice using the Pigpen Cipher.

Can you decrypt the Pigpen Cipher and help Marvin find his diamond?

Press the green flag to start.

To play this game on the Scratch website, and have the option of playing in full screen, click here.