Tutorial Questions on Cryptography & Network Security

Tutorials on Cryptography & Network Security (IV IT)

Tutorial-I (30-07-2026):

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 (22-08-2026):

1. What is meant by Fabrication?  What are Confusion and Diffusion properties of Modern Ciphers?
2. What are the various modes of operations of Block Ciphers?  Explain Cipher Block Chaining Mode.  
3. Explain in detail Feistel Block Cipher structure with neat sketch.
4. With a neat diagram, explain one round of DES algorithm.
5. Discuss the key management techniques that can be used for sharing the private key securely in Symmetric Encryption.

Tutorial-III (02-09-2026):

1. Explain the key expansion function of AES algorithm. 
2. Discuss in detail the implementation of RSA Algorithm.
3. In the RSA system, the public key of a given user is e=31, n=3599 what is the private key of the user?  Also, critically analyze the security aspects of RSA.
4. How to use Chinese Remainder Theorem to reconstruct integers from their residues modulo functions.
5. Explain in detail about the implementation of Diffie-Hellman Key Exchange.