SRM University 2007 B.Tech Computer Science and Engineering BANK FOR CS-356 NETWORK SECURITY - Question Paper

34. How many sub keys are used in IDEA? How are they generated?

PART B

1. Explain the various security attacks in detail.
2. Explain symmetric cipher model with neat diagram.
3. Explain any two substitution encryption techniques in detail.
4. State the rules for play fair encryption technique. Encrypt and decrypt the
message POSTPONED. presume the key to be HORLICKS.
5. Explain encryption and decryption in DES.
6. a) explain the strength of DES in brief.
b) discuss single round details of DES with a neat diagram.
7. Using hill cipher encrypt the plain text "friend" using the key
1 two 3
2 two 1
3 two 1
8. Using hill cipher encrypt the plain text "paymoremoney" using the key
17 17 5
21 18 21
two two 19
9. Using hill cipher encrypt the plain text "indian" using the key
one two 3
two two 1
three two 1
10. discuss the various block cipher modes of operation.
11. a) discuss subkeys and S-box generation in blowfish.
b) discuss single round details of blowfish.
12. a) discuss subkey generation in IDEA
b) discuss how encryption is done in IDEA.
13 a) provide the overall structure of IDEA.
b) discuss how decryption is done in IDEA.
14. Demonstrate RC5 decryption is the inverse of RC5 encryption
15. Demonstrate CAST128 decryption is the inverse of CAST 128
encryption.
16. discuss RC5 sub key generation and encryption in detail with
necessary diagram.
17. a) discuss RC5 key expansion with neat diagrams
b) discuss RC5 modes of operation.
18. discuss Blowfish encryption and decryption.
19. explain traffic confidentiality in detail.

Unit III
PART A

1. Find GCD of (60,24) using Euclid's Algorithm.
2. State Fermat's theorem
3. State Euler's theorem
4. Define Euler's Totient function.
5. Determine the subsequent
(a) F(41) b) F(27)
6. What is the primitive root of a number?
7. What is discrete logarithm?
8. Using Fermat's theorem obtain 3201 mod 11.

Earning:   Approval pending.