B.TECH - Semester 8 cryptography and network security Question Paper 2021 (feb)

Practice authentic previous year university questions for better exam preparation.

Sample Questions

Discuss Symmetric Cipher model
Encrypt the message "ATTACK POSSIBLE" using Caesar cipher assuming a suitable key.
State Fermat's theorem and Euler theorem and prove it using the values $a=7$ and $\mathrm{p}=13$
What are the functions of S/MIME?
What are the limitations of firewalls? Answer one full question from each Module. Each question carries 20 marks
(a) Explain how substitution and permutation techniques used in Feistal structure.
(b) Discuss the use of Feistal Structure in DES and strength of DES.
(a) What are the different block Cipher modes of operation in DES?
(b) Illustrate IDEA algorithm.
(a) What are the ingredients of Public key Cryptosystem?
(b) Discuss SHA with block diagram and write SHA algorithm.
(a) Explain Diffie-Hellman key exchange
(b) Consider Diffie-Hellman key exchange with common prime $q=11$ and a primitive root $\alpha=2$
(i) Show that 2 is a primitive root of 11 (ii) If user A has public key $Y_{A}=7$ what is the private key $X_{A}$ of A (iii) If user $B$ has $Y_{B}=5$ compute the key that is exchanged.
(a) What are the security services provided by ESP and AH? 10
(b) What are basic features of PGP?
(a) Explain IPSec Architecture.
(b) Explain transport and tunnel mode of IPSec. Module - IV
(a) Explain Encrypted tunnels. ..... 12
(b) Explain secure electronic transaction. ..... 8 OR
(a) Explain SSL record Protocol. ..... 10
(b) What are the capabilities of firewall? ..... 5
(c) Compare packet filters and application level gateway. ..... 5