B.Sc. (Computer Science) Sem 5 Information and Network Security Nov 2022 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 (a) (Attempt All. Multiple Choice Questions, 1 mark each) 10 Marks

1. (i) Which of the following is not an example of a substitution cipher? Options: a. Caesar cipher, b. Playfair cipher, c. Rail Fence cipher, d. Hill cipher
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2. (ii) A deliberate attempt to evade security services is called ____. Options: a. threat, b. attack, c. masquerade, d. repudiation
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3. (iii) Which security protocol is used at the transport Layer? Options: a. IPSec, b. PGP, c. SMIME, d. SSL
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4. (iv) A digital signature needs a(n) ____ system. Options: a. symmetric-key, b. asymmetric-key, c. private key, d. session key
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5. (v) Which of the following is a means to access a computer program or entire computer system bypassing all security mechanisms? Options: a. Backdoor, b. Masquerading, c. Phishing, d. Trojan Horse
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6. (vi) Passive attacks do not include ____. Options: a. modification of data stream, b. obtaining the information that is being transmitted, c. eavesdropping on transmission, d. the possibility of replay attack in future
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7. (vii) Public-key encryption is also known as ____. Options: a. asymmetric encryption, b. symmetric Encryption, c. single encryption, d. super encryption
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8. (viii) PKI stands for ____. Options: a. Parent Key Interface, b. Public Key Infrastructure, c. Protocol Key Infrastructure, d. Private Key Infrastructure
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9. (ix) AES has ____ different configurations. Options: a. one, b. three, c. four, d. five
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10. (x) One commonly used public-key cryptography method is the ____ algorithm. Options: a. RSS, b. RAS, c. RSA, d. RAA
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SECTION II - Q.1 (b) (Fill in the blanks from the pool: hashing, 64, 128, shared secret, steganography, cryptanalysis, transposition) 5 Marks

1. (i) ____ ciphers hide the message by rearranging the letter order without altering the actual letters used.
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2. (ii) SHA is a ____ algorithm.
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3. (iii) ____ is an alternative to encryption which hides the very existence of a message by some means.
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4. (iv) DES is a non-Feistel cipher that encrypts and decrypts a data block of ____ bits.
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5. (v) Private key cryptography uses a ____.
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SECTION III - Q.2 (Attempt the following, Any THREE) 15 Marks

1. (a) What is the CIA triad? Explain in detail.
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2. (b) Explain symmetric cipher model. Discuss different techniques used in traditional ciphers.
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3. (c) Explain DES cipher in detail.
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4. (d) Explain ECB block cipher mode of operation with its advantages and limitations.
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5. (e) Explain the differences between symmetric and asymmetric cryptography.
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6. (f) Discuss different categories of security services as per X-800 recommendations.
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SECTION IV - Q.3 (Attempt the following, Any THREE) 15 Marks

1. (a) Explain key generation process in Diffie-Hellman key exchange algorithm.
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2. (b) Discuss different approaches of distribution of public key in public key cryptography.
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3. (c) What is Message authentication? Discuss different approaches that can be used to achieve message authentication.
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4. (d) Explain various characteristics of Hash function.
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5. (e) Explain SHA algorithm.
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6. (f) Explain basic digital signature model. What security requirements do you feel can be achieved in digital communication by using digital signature?
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SECTION V - Q.4 (Attempt the following, Any THREE) 15 Marks

1. (a) Discuss any one protocol which is used to add security in email applications.
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2. (b) What is SSL? Discuss its protocol stack.
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3. (c) What is a honeypot? How does it facilitate intrusion detection?
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4. (d) What do you understand about malware? Explain any two types of malicious program.
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5. (e) Discuss the significance and limitations of firewalls.
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6. (f) What is the SET protocol? What business requirement does it fulfil?
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SECTION VI - Q.5 (Attempt the following, Any THREE) 15 Marks

1. (a) What is asymmetric key cryptography? Discuss its various applications.
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2. (b) Explain rail fence cipher with proper example.
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3. (c) Briefly explain Man in middle attack.
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4. (d) What is kerberos? Explain its different components.
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5. (e) Explain the key elements of public key infrastructure.
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6. (f) Discuss IPSec protocol with its different modes of operation.
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7. (g) What do you understand about security attacks? Discuss different types of attacks.
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8. (h) Explain the process of encryption and decryption using caesar cipher for plaintext "attack at dawn".
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