Exercise - Asymmetric Encryption
You installed Cryptool version 1.4.31 in Week 2. If you uninstalled Cryptool, you will need to reinstall the software as you did in Week 2. Follow the same instructions from unit 2 to open Cryptool. Click on File from the top menu bar and select New. Type This is a test. at least five times. Click on Encrypt/Decrypt from the top Menu Bar. Select Asymmetric encryption. In the pop-up window, select the only option available (this is a user profile)-SideChannelAt....... Click on Encrypt. The RSA-encrypted text will be displayed. Capture the screen and paste it in the Word template called Week 3 Template.docx.
In the next step, you are going to create a key pair. Note that asymmetrical encryption uses a key to encrypt (public key) and another key to decrypt (private key). Click on Digital Signature/PKI from the top menu bar and select PKI. Now choose Generate/Import keys. Complete the pop-up template. Select RSA and 1024 for Bit Length. Complete the User Data section on the right. Remember to select a PIN because every time you decrypt, you will need the PIN to have access to your PIN. Capture the completed pop-up window and paste it in your template. Click on Generate new key pair. Close the pop-up window. Now click on Encrypt/Decrypt and select Asymmetric Encryption. You will see your profile in the list of recipients. Capture this screen and paste in your template. This profile will be used in Week 4. Close the pop-up window.
Click on Encrypt/Decrypt and select RSA demonstration. RSA uses two prime numbers to generate the public key and private key. Enter a prime number (e.g., 13) for p and another prime number for q (e.g., 7). Now capture the screen and add it to your template. Notice your RSA modulus is 15. Click on Alphabet and number system option. Select Specify alphabet. Select Normal in RSA variant. Select Decimal in Number System. Now enter a message in the input row "This is a test." Click on Encrypt. Click OK on the pop-up message. Now capture this screen and paste it in your template.
Week 3 Template
1. Capture Screen 1 (Encrypt using SideChannel Profile.)
2. Screen for Key Pair
3. Creation of Profile
4. RSA Demonstration
5. Using Key Pair to Encrypt