Lab #2 – Assessment Worksheet

Lab #2 – Assessment Worksheet
Applying Encryption and Hashing Algorithms for Secure Communications

Overview
In this lab, you applied common cryptographic techniques to ensure confidentiality, integrity, and authentication. You created an MD5sum and SHA1 hash on a simple text file on a Linux virtual machine and compared the hash values of the original files with those generated after the file had been modified. Next, you used GnuPG to generate an encryption key pair and encrypted a message. Finally, you used the key pairs to send secure messages between two user accounts on the virtual machine and verified the integrity of the received files.
Lab Assessment Questions & Answers
1. Compare the hash values calculated for Example.txt that you documented during this lab. Explain in your own words why the hash values will change when the data is modified. The hash values will change when the data is modifie
2. Why are the MD5sum and SHA1sum hash values the same every time you calculate for the example.txt file? What if it were different when you recalculated the hash value at the other end? The MD5sum and SHA1 sum hash values the same every time is because it is from the same content of the file being used by original user.
3. If you want secure e-mail communications without encrypting an e-mail message, what other security countermeasure can you deploy to ensure message integrity? You can deploy to ensure message integrity is by using digital signatures, whether it is encrypted or not,
4. What is the –e switch used for with running the GnuPG command?
B. Encrypt
5. What is the difference between MD5sum and SHA1sum hashing calculations? Which is better and why? The difference between MD5sum and SHA1sum is that MD5: 128-bit/16-byte digest. Somewhat faster than SHA and SHA: 160-bit/20-byte digest. So SHA is more secure.
6. Name the cryptographic algorithms used in this lab. MD5sum and SHA1sum.
7. What do you need if you want to decrypt encrypted messages and files from a trusted sender? Use GPG to encrypt, decrypt, sign and verify files or emails.
8. What is the -d switch used for when running the GnuPG command? C. Decrypt
9. When creating a GnuPG private key, what are ways to create entropy? find * / && find * / && find * / && find * / && find * / && find * /
Part 2~ 6 Lab screen shot