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.
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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 5x2+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]