Find the value of $7^{2019} \mod 13$ using Fermat’s Little theorem. Define Euler totient function with an example. [5]
Authentication
1.
Define authentication system. Illustrate the need of mutual authentication over one way authentication with an example. [5]
Cryptographic Hash Functions and Digital Signatures
1.
Explain the generic model of digital signature process. Consider the two prime numbers 7 and 19. Select 29 as public key and 41 as private key. Encrypt the plaintext 4 and decrypt the cipher text 3 using RSA. [10]
2.
List the properties of hash function. Discuss the first pass of MD4. [5]
Introduction and Classical Ciphers
1.
Define CIA triad. State the encryption process of double and triple DES. What is the task of S-Box in DES? Discuss with an example. [10]
Malicious Logic
1.
What does intrusion mean? How the system detect intrusion? List any four types of firewall. [5]
Network Security and Public Key Infrastructure
1.
Describe the PKI trust model. [5]
2.
Define SSL protocol. Mention the services provided by PGP. [5]
Symmetric Ciphers
1.
Define Galois field with an example. Explain any two modes of block cipher encryption. Determine the quadratic residues of 7. [10]
2.
Decrypt the message 'GVPJ' using Hill cipher taking the key as {Row1 = 3 7, Row2= 5 12}. [5]
3.
Differentiate between Symmetric and Asymmetric cipher. Encrypt the message 'HELL' using the key 'FAIL' using Vernam cipher. [5]
4.
Divide $3x^2 + 4x + 3$ by $5x + 6$ over GF(7). [5]