Cryptography and Network Security Question Papers Andhra University

Cryptography and Network Security Question Papers

Andhra University

B. Tech (CSE) Degree Examination

Forth Year – Second Semester

CRYPTOGRAPHY AND NETWORK SECURITY

Effective from the admitted batch of 2004-2005

Time: 3 hrs
Max Marks: 70

First Question is Compulsory

Answer any four from the remaining questions

All Questions carry equal marks

Answer all parts of any question at one place

1. a) What is Non-repudiation?
b) What is denial service attack?
c) Distinguish between stream and block ciphers
d) Find the value of 89 mod 17
e) What is electronic money?
f) What is a digital envelope?
g) What is session key?

2. a) Describe the Diffie – Hellman key exchange algorithm and explain it with an example.
b) Alice and Bob want to establish a secret key using the Diffie – Hellman key exchange protocol using n = 11, g = 5, x = 2 and y = 3. Find the values A and B and the secret key.

3. Describe the data encryption algorithm.

4. a) What are the key requirements of message digests?
b) Describe the secure hash algorithm.

5. a) Describe the steps in the creation of a digital certificate.
b) Discuss XML security concepts.

6. a)Describe the time stamping protocol. What is its significance?
b) Describe pretty good privacy.

7. a) What is password based encryption? What are the problems associated with it?
b) Describe the KERBEROS protocol.

8. a) What are the characteristics of a good firewall implementation?
b) What is a VPN? Explain briefly about the VPN architecture.

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