Define discrete logarithms. How key generation, encryption and decryption is done in RSA. In a RSA cryptosystem, given p=13 and q=7, determine private key, public key and perform encryption and decryption for the text M='hi' using 0 to 25 for letters from a to z. [10]
2.
How Miller Rabin test is used for primality testing? Show whether the number 561 passes the test. [5]
3.
How does meet in middle attack work in Diffie Helman key exchange protocol? Explain. [5]
Authentication
1.
Give the formal definition of authentication system. Describe about one way and mutual authentication system.
$\begin{bmatrix} 3 & 2 \\ 5 & 7 \end{bmatrix}$
[5]
Cryptographic Hash Functions and Digital Signatures
1.
What are the applications of hash functions? Discuss how SHA-1 algorithm generates hash value from a given message. [10]
Introduction and Classical Ciphers
1.
Show that the set of integers is Ring under addition and multiplication. [5]
Malicious Logic
1.
What is malicious logic? How zombies are different from trojan horses? [5]
Network Security and Public Key Infrastructure
1.
List the stage of certificate life cycle. What are the types of firewalls? [5]
2.
Describe about IPSec. List the five services of PGP. [5]
Symmetric Ciphers
1.
Write down the encryption and decryption process at 2-DES and 3-DES. Explain the Fiestal cipher structure. Divide $5x^2 + 4x + 6$ by $2x + 1$ over GF(7). [10]
2.
Show encryption and decryption of "csit" using hill cipher having key, [5]
3.
How substitution ciphers are different from transposition ciphers? Given a message M="CSIT PROGRAM IS A HOT CAKE", encrypt M using Rail Fence cipher with rail size 3. [5]