VTU Previous Question Papers BE EC 8th Semester Network Security December 2010

VTU Previous Question Papers BE EC 8th Semester

Network Security December 2010


Note: Answer any FIVE full questions, selecting at least TWO questions from each part.


1 a. With a neat block diagram, describe the model for network security.

b.   Explain the types of attack on encrypted messages.

c.   Encrypt the message “we will meet tomorrow” using playfair cipher with a key ‘STORY’. Give the rules for encryption.


2 a. With a schematic diagram, explain the S-DES encryption and decryption process, highlighting the key generation phase.

b. Explain the counter mode of block ciphers. What are it’s advantages?


3 a. Distinguish between conventional and public key encryption methods.

b. In a public key system using RSA, the ciphertext received is C – 10. With a public key {e ~ 5, n ~ 35}, deduce the plaintext. Verify the answer by encryption process.

c.  With the help of a block diagram, explain the process of public key exchange with the help of certificate authority.


4 a. What is a hash function? What are the basic uses of a hash function?

b.   Explain the signing and verifying functions of Digital Signature Algorithm (DSA).


5    a. Briefly explain the SET requirements.

b. Explain the various phases of SSL handshake protocol. (12 Marks)


6 a. Explain the architecture of a distributed intrusion detection system. Give the major issues in the design.

b. Briefly explain the unix password scheme. What are the tlireats to this scheme? How are they overcome?


7    a. Give the taxonomy of malicious programs and explain in brief.

b. List and explain various virus countermeasures.

8     a. With neat diagrams, briefly explain the types of firewalls.

b.   With a neat diagram, explain the concept of trusted systems.

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