## March 9, 2010

### IT 1352-CRYPTOGRAPHY AND NETWORK SECURITY Question Papers

B.E/B.Tech DEGREE EXAMINATION, NOVEMBER/DECEMBER 2009
SEVENTH SEMESTERCOMPUTER SCIENCE AND ENGINEERING
IT 1352-CRYPTOGRAPHY AND NETWORK SECURITY Question Papers

PART A
1. what is cryptanalysis and cryptography?
2. Define threat and attack
3. What is the role of session key in public key schemes?
4. what is a zero point of an elliptic curve?
5. what are the functions used to produce an authendicator?
6. list the properties a digital signature should possess?
7. mention the scenario where kerberos scheme is prefered
8. what are the technical deficiencies in the kerberos version 4 protocol?
9. list the classes of intruders
10. give the type of viruses

PART B
11. a) Explain the OSI security architecture alon with the services available(16)
OR

b)(i) given 10bit key k=1010000010. determine K1,K2 where
P10= 3 5 2 7 4 10 1 9 8 6
p8 = 6 3 7 4 8 5 10 9
by using SDES key generation method.(10)
(ii) using the positional value of alphabets, represent them in 5 bit binary. aplly the transformation Ci=Ki EX-OR Pi,Pi=Ci EX-OR Ki where Pi="scheme" Ki="cipher". find the cipher text(6)

12. a)(i)perform encryption/decryption using RSA algorithm for the following:
p=3, q=11, e=7, m=5 (12)
(ii) what attacks are possible on RSA algorithm?(4)

OR

b)(i)given the key "MONARCHY" apply play fair to pain text "FACTIONALISM" to ensure confidentially at the destination, decrypt the ciphertext and establish authenticity(8)
(ii) apply public key encryption to establish confidentiality in the message from A to B. you are given m=67. KU={7,187}, KR={23,187}.(8)

13. a)(i)Apply the MAC on the cryptographic checksum method to authendicate build confidentiality of the message where the authentication is tied to message
M=8376, K1=4892, K2=53624071. (10)
(ii)what are the properties a hash function must satisfy? (6)

OR

b) explain MD5 message digest algorithm, with its logic and compression function.(16)

14. a)explain X.509 authentication servise and its certificates(16)

OR

b)(i)explain the services of PGP(12)
(ii)write down the functions provided by S/MIME(4)

15.a)(i)list the approaches for the intrusion detection(4)
(ii)explain firewall design principles, characteristics, and types of firewalls(12)

OR

b)(i)give the basic techniques which are in use for the password selection strategies(8)
(ii)write down the four generations of antivirus software(8)