Describe the Feistel Cipher structure. Given the key {2B, 7E, 15, 16, 28, AE, D2, A6, AB, F7, 97, 66, 01, 02, 03, 04}, compute the first 4 bytes of the next key after the first iteration, using the provided S-Box in AES.

Illustrate the man-in-the-middle attack in Diffie–Hellman key exchange protocol. Assume the prime number be 19 and 10 as its primitive root. Select 5 as private key and 4 as random integer. Find the ciphertext of M = 2 using Elgamal crypto system.

List the properties of hash function. Describe the algorithm for SHA-1.

Describe any three types of malicious logic.

Given the key "HELLOWORLD", encrypt the plaintext "TURINGTEST" using Playfair cipher.

Explain any two modes of block cipher encryption.

State Fermat’s theorem with an example. What is the implication of discrete logarithm?

Describe the working mechanism of digital signature algorithm

List and explain the types of firewall.

Decrypt the ciphertext "HI" using Hill Cipher where the key is

What is a digital certificate? Discuss the certificate life cycle.

Define authentication system. Discuss about challenge response system.