Computer Science Principles Unit 4 Chapter 1 Lesson 8: Encryption With Keys and Passwords

In this lesson, students learn about the relationship between cryptographic keys and passwords. Students explore the Vigenère cipher with a widget to examine how a cryptographic "key" can be used to encrypt and decrypt a message. Then, students use a tool that shows them about how long it would take to crack a given password using a standard desktop computer. Students experiment with what makes a good password and answer questions about the “human components” of cybersecurity.

Students will be able to:
- explain the relationship between cryptographic keys and passwords.
- explain in broad terms what makes a key difficult to “crack.”
- reason about strong vs. weak passwords using a tool that shows password strength.
- understand that exponential growth is related to an encryption algorithm’s strength.
- explain how and why the Vigenère cipher is a stronger form of encryption than plain substitution.
- explain properties that make for a good key when using the Vigenère Cipher.

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