Download AKTU B-Tech 7th Sem 2017-2018 NIT 701 Cryptography And Network Security Question Paper

SECTION A

Attempt all questions in brief.

1. a. Find GCD(1970, 1066) by using Euclid's Algorithm.

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2. b. What are the different factors on which Cryptography depends?
3. c. Compute the value of 5¹⁷ mod 11 & 11¹⁷ mod 5.
4. d. Find the value of Euler's Totient Number f(88).
5. e. What is Cryptanalysis?
6. f. Discuss Linear and Differential cryptanalysis.

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7. g. What is Birthday Attack?
8. h. Discuss Double & Triple DES.
9. i. Discuss Group & Ring with suitable axioms.
10. j. What is Security Attack? Discuss its various types.

2 x10 = 20

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SECTION B

Attempt any three of the following:

1. a. How E-Mail security is achieved? Discuss S/MIME with suitable steps & block diagram.
2. b. Discuss DES in detail with suitable block diagram.
3. c. Discuss MD-5 Algorithm with all required steps and suitable block diagram.
4. d. Describe IDEA encryption and decryption in brief. Also explain. How can we generate cryptographically secure pseudorandom numbers?

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5. e. What do you understand by Elgamel encryption system? Explain its encryption and decryption?

10 x 3 = 30

SECTION C

Attempt any one part of the following:

1. (a) Explain Digital Signature. Discuss signing & verifying process of Digital Signature Algorithm (DSA) in detail with suitable steps.
2. (b) Discuss X.509 digital certificate format. What is its significance in cryptography?

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10 x 1 = 10

Attempt any one parts of the following:

1. (a) Why Message Authentication is required? Discuss working of MAC with suitable block diagram. Also discuss HMAC & CMAC in detail.
2. (b) What is Hash Function? Discuss SHA-512 with all required steps, round function & block diagram.

10 x 1 = 10

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Attempt any one parts of the following:

1. (a) Discuss Diffie Hellman key exchange method. Let q = 353, a=3, X_A= 97 and X_B = 233. Then Compute Y_A, Y_B, K_A& K_B using Diffie Hellman.
2. (b) Discuss Public Key Cryptosystem. Explain RSA algorithm with suitable steps. Let p= 17, q=11, e=7 and d=23. Calculate the public key & private key and show encryption.
3. (c) What do you understand by Chinese Remainder Theorem? Solve the following congruent equations by Chinese remainder theorem:
   1. X = 2 mod 3
   2. X = 3 mod 5

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5 x 2 = 10

Attempt any two part of the following:

1. (a) Explain Finite field of the form GF (p) & GF (2ⁿ ) with suitable example.
2. (b) What is Block Cipher? Discuss Block Cipher Mode of Operations.

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3. (c) What do you understand by Feistel cipher structure? Explain with suitable block diagram.

5 x 2 = 10

Attempt any one part of the following:

1. (a) What is Kerberos? Discuss Kerberos version 4 in detail.
2. (b) Write short note on the following:
   1. SET

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   2. Intrusion Detection
   3. Firewall
   4. AES

10 x 1 = 10

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