Lab #2 – Assessment Worksheet
Applying Encryption and Hashing Algorithms for Secure
Communications
IS4560
Course Name and Number: _____________________________________________________
Student Name: ________________________________________________________________
Instructor Name: ______________________________________________________________
Lab Due Date: ________________________________________________________________
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.
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?
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?
4. What is the –e switch used for with running the GnuPG command?
A. Extract
B. Encrypt
C. Export
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5. What is the difference between MD5sum and SHA1sum hashing calculations? Which is better
and why?
6. Name the cryptographic algorithms used in this lab.
7. What do you need if you want to decrypt encrypted messages and files from a trusted sender?
8. What is the -d switch used for when running the GnuPG...