Lab Assignment: Advanced Encryption Standard (AES)

This exercise uses theAdvanced Encryption Standard (AES). The United States National Institute of Standards and Technology (NIST) adopted AES as Federal Information Processing Standards Publications 197(FIPS PUB 197) in 2001. AES supports key lengths of 128, 192, and 256 bits; JavaScrypt uses 256 bit keys exclusively.

For this exercise, you will need to use two different e-mail accounts (i.e., your Strayer email account and your personal email account). You will be creating an encrypted message and sending it from your first e-mail account to your second e-mail account.

Instructions

• Capture a screenshot as you complete each one of the lab steps and paste it in the designated spot below each step.

If there is a question in a step, your response should be included directly under the screenshot of that step.

Lab Steps:

1. Go to the JavaScrypt Encryption and Decryption page, located at http://www.fourmilab.ch/javascrypt/javascrypt.html

2. Create a key and enter it into the text box under the "Key" section. (The text option button under the textbox should be selected.) Next, click the "Generate" command button. Copy the contents of the "Key" text box to a notepad file because you will need it later.

3. Then, go to the "Plain Text"" box immediately underneath the "Key" text box and enter text that you want to encrypt. (The "Codegroup" option button under the textbox should be selected.) Click the "Encrypt" command button.

4. Look at the "Cipher Text" text box located below the "Encrypt" command button. Explain what is there.

5. Login to your second e-mail account and open a new email.

6. Copy the contents of the "Cipher Text" text box into the body of the email that you will be sending to your second email account.

7. Clear the contents of each of the "Key," "Plain Text," and "Cipher Text" text boxes.

8. Send the email from your first email account to your second email account.

9. Go to your second email account and open the email that you sent to yourself. Copy the encrypted message and paste it into the "Cipher Text" text box at http://www.fourmilab.ch/javascrypt/javascrypt.html. Click the "Decrypt" command button.

10. Look back in the "Plain Text" text box. What do you see? Discuss what happened.

11. Now, enter the key (plain or encrypted) into the "Key" text box. Which key did you enter? Can you enter the plain (unencrypted) key or do you have to use the encrypted one in order for the contents of the encrypted "Cipher Text" text box to be unencrypted and displayed in the "Plain Text" text box? Provide a rationale for your response.

12. If a person does not have the original encrypted key, can he or she encrypt the original key that he or she entered in the "Key" text box? Provide a rationale for your response.Note: No screenshot is needed for this step.

13. Explain the differences, if any, between using AES encryption versus a DES one. Note: No screenshot is needed for this step.

14. Why do many consider AES encryption more secure than DES? Provide a rationale for your response. Note: No screenshot is needed for this step.