Distance Learners:
Below is the lesson plan that you usually see me write on the dry erase board in class.
I have set up the exact same class on a Google Doc in your CSP class folder. This will allow you to enter "Journal" questions I pose to you and other Activities. Thus, I recommend you go straight to the Google Doc:

Access Google Doc I set up for you in your CSP folder titled:   “U4Ch1L8_Encryption With Keys & Passwords.”
When you complete today's class assignments, Email me at:  "john.harrington@student.sthelenaunified.org"  so that I can give you credit.

U4Ch1L8_ Encryption With Keys and Passwords

Purpose: Students will use a Vigenère cipher to learn about the relationship between cryptographic keys/passwords and the Encryption & Decryption of a Message.

Vocabulary

• Computationally Hard

Code.org: Vigenere Cipher

• Read the explanation as to how the Vigenere Cipher tool works.
• Start simple: enter a simple Text Message & enter a simple Key.
• Select a slow encryption speed.
• Select Play, but hover your mouse over the pause button.
• Now watch. Can you figure out how the “Ciphertext” is being created?

Try This:

• Enter a test message.
• Enter a secret key.
• Select Encrypt.
• Select play.
• When it finishes creating the Ciphertext…copy it and paste it in the “Text Message” field.
• Keep the same secret key.
• Select Decrypt.
• Select Play.
• The original message should now appear in the Cipher Text.

Go ahead and play with the Vigenere Cipher tool.

Journal: To Crack a Ciphertext, what would you need to know?

Activity: Test the Strength of your Password.
Your Password acts as a “Key”. Let’s test the strength of your password from being cracked. Go to “How Secure Is My Password.” Enter some fake passwords to see their strength. Add the following to check the strength:

• More characters (keep adding and testing).
• Capital
• Number
• Exclamation Point

Try This:

• Create a few passwords using 8 lowercase ASCII characters (a-z).  What’s the longest amount of time-to-crack you can generate?
• Using any characters on the keyboard, what’s the longest amount of time-to-crack you can generate with an 8-character password?
• As you try passwords, what seems to be the single most significant factor in making a password difficult to crack?  Why do you think this is?
• Opinion: Is an 8-character minimum a good password length for websites to require? Give your opinion, yes or no, and explain why you think that.
•  

Video: Encryption & Public Keys
Journal:

• What is the difference between “cracking” a code and “decrypting” a message?
• Would you feel comfortable sending your password over the Internet using a substitution cipher? Explain.
• State one thing you can do to produce a better encrypted message using a Vigenere cipher?

If time remains…play the Encryption Terminology Matching Quiz…#6!