Anna University Chennai 2010-1st Sem B.E Computer Science and Engineering Anna University - /B.Tech , EMR/EMR Seventh Semester IT 1352 – CRYPTOGRAPHY AND NETWORK SECURITY (Common to Sixth nformation

B.E/B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2010.
7th Semester
Computer Science and Engineering
IT 1352 CRYPTOGRAPHY AND NETWORK SECURITY
Regulation 2004
(Common to 6th Semester info Technology-Regulation 2005)

Time: 3 hours Maximum : 100 marks

ans ALL ques.
PART A - (10 x two = 20 marks)

1. How will you perform attack on Hill Cipher?
2. When the number of rounds in DES is less, what type of cryptanalysis is easier?
3. What is the role of a primitive root in Diffie-Hellman Key exchange?
4. State how timing attack in RSA can be avoided.
5. provide an example where one-way authentication is used.
6. List the requirements of a hash functions.
7. State the services given by IPSec.
8. Differentiate SSL connection from SSL session.
9. discuss the term Baston Host.
10. List the classes of intruders.


PART B - (5 x 16 = 80 marks)

11. (a) discuss the concept of monoalphabetic cipher and polyalphabetic substitution ciphers with
examples. (16)

Or

(b) (i) elaborate the relative merits and demerits of block cipher modes of operations ? (8)
(ii) When do you say an algorithm in computationally secure ? Can you suggest an encryption
scheme which is unconditionally secure ? discuss. (8)

12. (a) (i) discuss the Rivest Shamir Adleman algorithm with an application. (10)
(ii) obtain whether 11111 has unique inverse modulo 12345. (6)

Or

(b) (i) How do you represent the message in Elliptic Curve ? discuss the processing steps
involved in encryption and decryption. (10)
(ii) obtain the integers uniquely described by the residues (1,0,0) and (2,0,0) in Z105. obtain
the sum of integers mod 105 by adding the residues. Use Chinese remainder theorem. (6)

13. (a) discuss the MD5 and SHA-1 hashing function with an example. (16)

Or

(b) Illustrate the Digital Signature algorithms in detail with an application. (16)

14. (a) (i) How does Kerberos authenticate services from any servers? (8)
(ii) elaborate the basic requirements expexted from SET? what is the role of Dual signatures
in meeting the requirements ? (8)

Or

(b) (i) Illustrate the implementations of IPSec.
(ii) elaborate the different services given by PGP? How? (8)

15. (a) What is firewall? discuss the kinds of firewall with an example. (4+12)

Or

(b) (i) How are passwords handled and managed? (8)
(ii) How does a worm propagate? Illustrate with an example. (8)

Earning:   Approval pending.