STUPIDSID
1(a)
What are block ciphers? Explain with examples the CBC and ECB modes of block ciphers.
5 M
1(b)
Encrypt the string " This is an easy task" using a playfair cipher with key "monarchy".
5 M
1(c)
Define authentication and non-repudiation and show with examples how each one can be achieved.
5 M
1(d)
Describe triple DES with two DES keys. Is main in the middle attack possible on triple DES?
5 M
2(a)
A and B decide to use Diffie Hellman algorithm to share a key. They choose p=23 and g=5 as the public parameters. Their secret keys are 6 and 15 respectively. Compute the secret key that they share.
10 M
2(b)
Compare DES and IDEA. Explain the round key generation scheme in both these alorithms.
10 M
3(a)
What are the different types of viruses and worms? How do they propogate?
10 M
3(b)
What are the various ways for memory and address protection in Operating systems? How is authentication achieved in O.S?
10 M
4(a)
Explain briefly with examples, how the following attacks occur:
i) Salami attack
ii) Denial of service attack
iii) session hijacking attack
iv) Cross-cite scripting attack
i) Salami attack
ii) Denial of service attack
iii) session hijacking attack
iv) Cross-cite scripting attack
10 M
4(b)
How is security achieved in the transport and tunnel modes of IPSec? Describe the role of AH and ESP.
10 M
5(a)
How is confidentiality achieved in emails using either S/MIME or PGP?
5 M
5(b)
A and B wish to use RSA to communicate securely. A chooses public key (e,n) as (7,247) And B chooses public key (e,n) as (5,221). Calculate their private keys. What will be the cipher text sent byA to B if A wishes to send message m=5 securely to B?
10 M
5(c)
What is a digital signature? Explain andy digital signature algorithm.
5 M
6(a)
Comapare and contrast(Any two):
i) Block and stream ciphers
ii) MD-5 versus SHA
iii) KDC versus CA
i) Block and stream ciphers
ii) MD-5 versus SHA
iii) KDC versus CA
10 M
6(b)
What are firewalls. Explain the different types of firewalls and mention the layer in which they operate.
10 M
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