Tribhuvan University
Bachelor of Computer Application
Semester 8 · TU Board 2025
Course Title: Information Security (CACS459)
Full Marks: 60Pass Marks: 24Time: 3 hours
Candidates are required to answer the question in their own words as far as possible.
Group B
Attempt any SIX question.(6 × 5 = 30)
- 2.5
What is security? Explain different type of passive attack with example. [1+4]
Answer comingAlso asked in 2023
- 3.5
What is confusion and diffusion? Decrypt the cipher text CDFNFTDTSBEQ with the key FOHSS using Playfair cipher. [2+3]
- 4.5
What is Group? Find the GCD (72345, 43215) using Euclidean algorithm [1+4]
- 5.5
Explain Key Schedule of AES algorithm. [5]
- 6.5
What is token based authentication? Explain core component of trust framework. [1+4]
- 7.5
What is digital signature? List and explain the phase of computer virus? [2+3]
- 8.5
What is audit trail? Why is it important in security auditing? [2+3]
Group C
Attempt any TWO questions(2 × 10 = 20)
- 9.10
What do you mean by "Feistel Structure for Block Ciphers"? Explain with block diagram. How can a number can be tested for primality testing using Miller-Rabin algorithm? Explain with suitable example. [5+5]
- 10.10
Explain the properties of hash functions. Discuss how hash value is generated using SHA-1 algorithm with neat diagram. [3+7]
Answer comingAlso asked in 2024
- 11.10
What is Pretty Good Privacy (PGP)? Explain any five services provided by PGP for email security. [2+8]
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