B.Sc. (Computer Science) Sem 5 Information and Network Security Mar 2026 Question Paper - Mumbai University | munotes

Questions asked in this paper

• N.B. (1) All questions are compulsory. (2) Figures to the right indicate marks. (3) Illustrations, in-depth answers and diagrams will be appreciated. (4) Mixing of sub-questions is not allowed.

SECTION I - Q.1 (Attempt ANY FOUR from the following) 20 Marks

1. (a) What is an Active Attack in network security? Explain any three types of active attacks in detail.
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2. (b) What is Computer Security and discuss its objectives?
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3. (c) Apply the Caesar cipher to encrypt "HELLO WORLD" with key 3 and decrypt it back to the original message.
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4. (d) Write a short note on AES.
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5. (e) Explain Monoalphabetic substitution with an example.
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6. (f) Differentiate between stream cipher and block cipher.
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SECTION II - Q.2 (Attempt ANY FOUR from the following) 20 Marks

1. (a) Describe how Public-Key Infrastructure (PKI) helps in secure communications?
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2. (b) Write a short note on Kerberos.
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3. (c) What is HMAC? How it works?
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4. (d) Explain the Diffie-Hellman key exchange algorithm with an example.
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5. (e) Define a Digital Signature and describe how it works?
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6. (f) Explain the various fields of an X.509 certificate.
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SECTION III - Q.3 (Attempt ANY FOUR from the following) 20 Marks

1. (a) Write a short note on packet filtering firewall.
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2. (b) Describe how PGP secures email messages and discuss its main features.
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3. (c) What is a DDoS attack? Explain its working and impact.
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4. (d) Explain the different techniques of Intrusion Detection Systems.
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5. (e) Explain the key components of IPSec.
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6. (f) Describe the purpose and main features of the Secure Electronic Transaction protocol.
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SECTION IV - Q.4 (Attempt ANY FIVE from the following) 15 Marks

1. (a) What is SSL? Describe its working mechanism.
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2. (b) Differentiate between Cryptography and Steganography.
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3. (c) What is Virus? Describe different types of Viruses.
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4. (d) Compare S/MIME and PGP in email security.
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5. (e) Discuss the role of firewalls in protecting organizational networks.
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6. (f) Define an intruder and intrusion.
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Read from the scan above, so a character or two may differ. The scan is the original.