1
Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
MCA SEMESTER-IV • EXAMINATION WINTER 2018
Subject Code: 3640004 Date: 27/11/2018
Subject Name: Network Security
Time: 10.30 am to 01.00 pm Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1

Answer the following questions.
1. List out categories of active attack.
2. What is replay?
3. What is stream cipher?
4. What is brute-force attack?
5. What is the first step in AES round?
6. What is Public-Key Encryption?
7. What is Session key?
07

Answer the following questions.
1. An encrypted hash of a message is a type of
2. RC4 is an example of
3. The power of counter mode is
4. A random number in key exchange is popularly known as
5. SSH is a protocol for
6. Extended service set is
7. Secret key algorithms are also known as
07
Q.2

1. Explain Security Mechanism.
2. Explain Network Security Model with supporting diagram.
03
04

What are the essential ingredients of a symmetric cipher? Explain Feistel Cipher Structure.
07
OR

What is symmetric encryption? Explain ECB and CBC mode.
07
Q.3

What is a message authentication code? List three approaches to message authentication.
07

Explain Diffie-Hellman Key Exchange algorithm.
07
OR

What are the principal ingredients of a public-key cryptosystem? List and briefly define three uses of a public-key cryptosystem.
07
Q.4

1. What is the job of SSL Record Protocol?
2. Write any three important differences between SSL and TLS
04
03

What is the basic building block of an 802.11 WLAN? List and briefly define IEEE 802.11 services.
07
2
OR
Q.4

List out the security services provided by WTLS and describe with appropriate example.
07

Explain Kerberos version 4 in detail.
07
Q.5

What are the five principal services provided by PGP? Why does PGP generate a signature before applying compression?
07

1. Write and explain any three applications of IPsec.
2. How security associations are combined in IPsec? Give appropriate examples.
03
04
OR
Q.5

What is Intrusion? Discuss intrusion detection techniques.
07

Why firewall is needed in a secure network? Describe the various types of Firewall.
07