Public Key Cryptography

Overview

Students will learn about and practice public key encryption. Focus on asymmetric algorithms where the process is not the same in both directions.

Purpose

Objectives

Students will be able to:

• Identify the need for public key cryptography.
• Define a general procedure for asymmetric encryption.
• Identify the strengths and potential weaknesses of public key cryptography.

Preparation

• Print CS Unplugged Activity
• Signup for and enroll students in Code.org CSP course

Links

• For the Teacher
  • http://csunplugged.org/wp-content/uploads/2014/12/unplugged-18-public_key_encryption_0.pdf
  • https://studio.code.org/
  • http://tuftsjournal.tufts.edu/2010/01_1/professor/01/
• For the Students
  • https://websitebuilders.com/how-to/stay-safe/secure-transactions/

    Vocabulary

Teaching Guide

Getting Started:

Numberphile - Public Key Encryption

• https://www.youtube.com/watch?v=M7kEpw1tn50 Graphic of Apple’s SMS privacy
• https://techcrunch.com/2014/02/27/apple-explains-exactly-how-secure-imessage-really-is/

  Activity

• CS Unplugged Public Key Encryption Activity

Activity

• Code.org CSP Public Key Encryption
• Students will need a code.org account and to be registered in a CSP course you’ve setup.

Wrap-up

• Khan Academy video on public key encryption
  • https://www.youtube.com/watch?v=YEBfamv-_do

    Assessment Questions

• Describe to a person who knows nothing about encryption why public key encryption is secure and is hard to crack.
• Explain in your own words what the modulo operation does. You may use the analogy of a clock in your answer if you like.
• In symmetric encryption the same key is used to encrypt and decrypt a message. In asymmetric encryption different keys are used to encrypt and decrypt. Give at least one reason why asymmetric encryption is useful

Extended Learning

Read: The Code Book - Chapter 5 Alice and Bob go Public

After reading chapter 5 of The Code Book, reflect on the following questions and create a blog post on this topic. As with the previous blog posts, the idea is to have the post be informative, informal, as though you were independently interested in this topic and are writing a blog based on your curiosity.

This chapter focused on public key encryption.

• How is public key encryption possible?
• Who were the key players in developing public key encryption?
• Why do we believe the process of encrypting is not crack-able?
• What are the potential issues with encryption as computers increase in computing power?
• Who are some of the hidden figures in this field? Why did they not initially get credit for their work?

Raspberry Pi: Buid an OctaPi

• https://projects.raspberrypi.org/en/projects/build-an-octapi
• https://projects.raspberrypi.org/en/projects/octapi-public-key-cryptography

Standards Alignment

Indiana - CS3S-1.2 Indiana - CS3S-2.1

License

Cyber Security Curriculum is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.