Tribhuvan University
Bachelor of Science in Computer Science and Information Technology
Semester 5 · TU Board 2078
Course Title: Cryptography (CSC316)
Full Marks: 60Pass Marks: 24Time: 3 hours
Candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.
Group A
Attempt Any Two Questions(2 × 10 = 20)
- 1.10
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.
- 2.10
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.
- 3.10
Define Galois field with an example. Explain any two modes of block cipher encryption. Deterimine the quadratic residues of 7.
Answer comingAlso asked in 2082, 2081
Group B
Attempt Eight Questions(8 × 5 = 40)
- 4.5
What does intrusion mean? How the system detect intrusion? List any four types of firewall.
- 5.5
Decrypt the message "GVPJ" using Hill cipher taking the key as {Row1 = 3 7, Row2 = 5 12}.
- 6.5
Describe the PKI trust model.
Answer comingAlso asked in 2081
- 7.5
Define authentication system. Illustrate the need of mutual authentication over one way authentication with an example.
- 8.5
Find the value of 7^2019 MOD 13 using Fermat's Little theorem. Define Euler totient function with
an example. - 9.5
List the properties of hash function. Discuss the first pass of MD4.
- 10.5
Differentiate between Symmetric and Asymmetric cipher. Encrypt the message "HELL" using
the key "FAIL" using Vernanm cipher. - 11.5
Divide 3x^2 + 4x +3 by 5x +6 over GF(7).
Answer comingAlso asked in Model question
- 12.5
Define SSL protocol. Mention the services provided by PGP.
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