This unplugged lesson will allow students to encrypt and decrypt message using the Caesar Cipher letter shift method of encryption. Cover the process of how this method works by doing an example and explaining the process of shifting the plaintext by the letter shift value to create the encrypted cipher text.

This lesson is designed to teach students basic encryption using the Caesar cipher method. This is a simple letter shift cipher that takes a plaintext message and encrypts it into cipher text by shifting each letter of the message by a value between 1 and 25 (1 less than the total number of letters in the English alphabet). This technique was used by Julius Caesar to encrypt messages by shifting each letter of the message by 3 letters. The message would be decrypted by taking each letter and shifting back 3 letters to reveal the plaintext message.

The student or class will watch a video clip about ciphers, specifically Caesar Ciphers.  Next students will learn more about encryption and decryption through the use of "keys".  Lastly, students will be introduced to the career path choices as a Cyber-security analyst. This is one lesson out of a series of five, and can be used alone, or with the some or all of the other four lessons.

This lesson is presented by Code.org
Lesson 8: Cybersecurity - Simple Encryption

From the website:
OVERVIEW
"In this lesson, students are introduced to the need for encryption and simple techniques for breaking (or cracking) secret messages. Students try their own hand at cracking a message encoded with the classic Caesar cipher and also a Random Substitution Cipher. Students should become well-acquainted with idea that in an age of powerful computational tools, techniques of encryption will need to be more sophisticated. The most important aspect of this lesson is to understand how and why encryption plays a role in all of our lives every day on the Internet, and that making good encryption is not trivial. Students will get their feet wet with understanding the considerations that must go into making strong encryption in the face of powerful computational tools that can be used to crack it. The need for secrecy when sending bits over the Internet is important for anyone using the Internet."

OBJECTIVE
"Explain why encryption is an important need for everyday life on the Internet.
Crack a message encrypted with a Caesar cipher using a Caesar Cipher Widget
Crack a message encrypted with random substitution using Frequency Analysis
Explain the weaknesses and security flaws of substitution ciphers"

The lesson is mapped out for teachers. It is easy to follow and includes vocabulary to cover, links to the necessary materials, and a teaching guide with background information, tips, and prompts.

AGENDA
Warm Up (10 min)
Classic Encryption - The Caesar Cipher
Activity (35 min)
Part 1 - Crack a Caesar Cipher
Part 2 - Crack a Random Substitution Cipher
Wrap Up (15 min)
Video: Encryption and Public Keys
Discussion
Career Discussion

Overview: This lesson is presented by Code.org
Lesson 8: Cybersecurity - Simple Encryption

From the website:
OVERVIEW
"In this lesson, students are introduced to the need for encryption and simple techniques for breaking (or cracking) secret messages. Students try their own hand at cracking a message encoded with the classic Caesar cipher and also a Random Substitution Cipher. Students should become well-acquainted with idea that in an age of powerful computational tools, techniques of encryption will need to be more sophisticated. The most important aspect of this lesson is to understand how and why encryption plays a role in all of our lives every day on the Internet, and that making good encryption is not trivial. Students will get their feet wet with understanding the considerations that must go into making strong encryption in the face of powerful computational tools that can be used to crack it. The need for secrecy when sending bits over the Internet is important for anyone using the Internet."

OBJECTIVE
"Explain why encryption is an important need for everyday life on the Internet.
Crack a message encrypted with a Caesar cipher using a Caesar Cipher Widget
Crack a message encrypted with random substitution using Frequency Analysis
Explain the weaknesses and security flaws of substitution ciphers"

The lesson is mapped out for teachers. It is easy to follow and includes vocabulary to cover, links to the necessary materials, and a teaching guide with background information, tips, and prompts.

AGENDA
Warm Up (10 min)
Classic Encryption - The Caesar Cipher

Activity (35 min)
Part 1 - Crack a Caesar Cipher
Part 2 - Crack a Random Substitution Cipher

Wrap Up (15 min)
Video: Encryption and Public Keys
Discussion
Career Discussion

***This lesson can be adapted for younger students but material covered aligns best with the current 8th grade Impacts of Computing Standards.