16-04-2012, 02:31 PM
CRYPTOGRAPHY & N/W SECURITY IMPORTANT QUESTIONS
CRYPTOGRAPHY & NW SECURITY IMPORTANT QUESTIONS.doc (Size: 32.5 KB / Downloads: 53)
1. What is Shannon’s Theory of Confusion and Diffusion?What do you understand by Feistal Cipher Structure? Illustrate with some suitable example.
2. Explain Feistel Encryption and Decryption Algorithm.
3. How does Meet-in-the-Middle Attack improve the vulnerability in Double-DES? What are the advantages of implementing Triple-DES with two keys?
4. Explain the principle of Diffrential Cryptanalysis. List and briefly define types of cryptanalytic attacks.
5. Describe in brief IDEA encryption and decryption. Also explain How can we generate cryptographically secure pseudorandom numbers?
6. Explain the Blowfish Cryptographic algorithm. Also differentiate between differential and linear cryptanalysis.
7. A Hill Cipher uses the following key for enciphering the message:-
K= [3 2]
[5 7]
Obtain the decryption key to be used for deciphering the ciphertext.
8. Describe Fermat’s & Euler’s Theorem? What is Euler’s Totient Function
and also describe its limitations. Find 3^201 mod 11.
9. Define the Chinese Remainder Theorem and its application. Find the value of x for the following sets of congruence using the Chinese Remainder Theorem.
10. Perform encryption and decryption using RSA Algorithm for p=17, q=11, e=7, m=88 where m= plaintext or message.
11. In a Diffie-Hellman-Key-Exchange Algorithm, let the prime number be 353 and one of its primitive root be 3 and let A & B select their secret keys XA=97 and XB=233.Compute public key and common secret key of A& B.
12. Describe Fermat’s & Euler’s Theorem? What is Euler’s Totient Function and also describe its limitations. Find 3^201 mod 11.
13. Define the Chinese Remainder Theorem and its application. Find the value of x for the following sets of congruence using the Chinese Remainder Theorem.
14. What is Elliptic Curve Cryptosystem? How it is implemented in Public-Key Cryptography?
15. Show how RSA can be used for performing Digital Signature Standard. Discuss Proof of Digital Signature Algorithm.Perform encryption and decryption using RSA Algorithm for p=17, q=11, e=7, m=88 where m= plaintext or message.
16. Explain AES(Advanced Encryption Standard.)
17. In MD5 algorithm, what is the number of padding bits if the length of original message is 2590-bits? Do we need padding if the length of the original message is already a multiple of 512-bits?
18. What is Digital Signature? Describe Digital Signature Standard (DSS)? Why each signature requires a new value of key?
19. Compare the security of Hash Function & MAC against brue-force atack and cryptanalysis. What basic & logical functions are used in MD5 and SHA-1 Logic? Give Comparison of MD5 SHA-1.
20. In a Diffie-Hellman-Key-Exchange Algorithm, let the prime number be 353 and one of its primitive root be 3 and let A & B select their secret keys XA=97 and XB=233.
Compute public key and common secret key of A& B.
21. Describe the Birthday Attack against any Hash Function. Give the mathematical basis of the attack.