Tutorial Questions on Information Security

Tutorials on Informatin Security

Tutorial-I (04-08-2026):

1. Explain the Play Fair cipher algorithm? Encrypt the message ‘MY BALLOON’ using the key ‘MONARCHY.
2. Encrypt the message “this is an exercise” using Caesar Cipher with key = 20.  Ignore the space between words. 
3. Encrypt the message “the house is being sold tonight” using Vigenere cipher with key = “dollars”.  Ignore the space between words.
4. Use PlayFair cipher with keyword = “Health” to encipher the message “Life is Full of Surprises”
5. Use Hill Cipher to encipher the message “WE LIVE ON EARTH” using the key = “DCFH”

Tutorial-II (12-08-2026):

1. Explain HMAC.
2. Discuss about authentication requirements.
3. Discuss about message authentication and hash functions.
4. Explain the Diffie-Hellman key exchange algorithm.
5. Explain the SHA-512 algorithm. Illustrate with an example.

Tutorial-III (05-09-2026):

1. Assume client C wants to communicate with a server S. How can it be achieved using Kerberos protocol.?
2. What is one-way authentication? Also explain the X.509 certificate formats.
3. Mention three variations of digital signatures and briefly state the purpose of each.
4. What do you mean by PGP? Explain the working principle of PGP.
5. In PGP, what is the probability that a user with N public keys will have at least one, duplicate key ID?