Download VTU BE 2020 Jan CSE Question Paper 15 Scheme 6th Sem 15CS61 Cryptography Network Security and Cyber Laws

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15CS61
Sixth Semester B.E. Degree Examination, Dee
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1

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.2020
Cryptography, Network Security and Cyber Laws
Time: 3 hrs. Max. Marks: 80
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2
Note: Answer
a. What do
attacks.
b. Using Extended

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a. Design
b. Consider
k=
(i) What
any FIVE

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you mean
known plain
a Hill cipher
(
25 3 7

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5 9 21
11 8 13
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is the cipher

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full questions, choosing ONE full question from each module.
Module- 1
Euclidean
by cyber attack? List and explain main motives of launching cyber
(08 Marks)

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algorithm find the inverse of 12 modulo 79. (08 Marks)
OR
test attack to obtain the key used in the Vigenere cipher. (08 Marks)
m = 3 (block size = 3) with key k shown below:
text corresponding to the plaintext = (VOW)?

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(ii) What is the plain text corresponding to the ciphertext = (TQX)? (08 Marks)
Module-2
3 a. List and explain RSA operations. (08 Marks)
b. The modulus in a toy implementation of RSA is 143
(i) What is the smallest value of a valid encryption key and the corresponding

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decryption key?
(ii) For the computed encryption key and plaintext = 127, what is the corresponding
ciphertext? (08 Marks)
OR
4 a. In what way are the properties of the cryptographic hash ? the one way property and

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collision resistance relevant to the security provided by the MAC? Explain. (08 Marks)
b. Consider the digital signature created using the Signer's private key operation but without
the hash function i.e., sign(m) = EA
pr
( m)

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Demonstrate how a forged signature may be created using this definition of a digital
signature. (08 Marks)
Module-3
5 a. What do you mean key management? Explain the fields of an X.509 certificate. (06 Marks)
b. List and explain PKI Architectures. (06 Marks)

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c. Define Dictionary Attacks. Explain Attack types. (04 Marks)
OR
6 a. Design the Needham ? Schroeder protocol.
b. Define Kerberos. Explain Kerberos message sequence.
c. Explain SSL Record Layer Protocol.

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(06 Marks) ,
(05 Marks)
(05 Marks)
I of 2
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USN
nM ?
:
1: ) ?
/

--- Content provided by FirstRanker.com ---

15CS61
Sixth Semester B.E. Degree Examination, Dee
.
./014/1
1

--- Content provided by FirstRanker.com ---

.2020
Cryptography, Network Security and Cyber Laws
Time: 3 hrs. Max. Marks: 80
U
U

--- Content provided by FirstRanker.com ---

r
U
et
, :=
?...7

--- Content provided by FirstRanker.com ---

0
;
II
oc
N

--- Content provided by FirstRanker.com ---

T.;
v
a.)
o
?

--- Content provided by FirstRanker.com ---

2
Note: Answer
a. What do
attacks.
b. Using Extended

--- Content provided by FirstRanker.com ---

a. Design
b. Consider
k=
(i) What
any FIVE

--- Content provided by FirstRanker.com ---

you mean
known plain
a Hill cipher
(
25 3 7

--- Content provided by FirstRanker.com ---

5 9 21
11 8 13
/

is the cipher

--- Content provided by FirstRanker.com ---

full questions, choosing ONE full question from each module.
Module- 1
Euclidean
by cyber attack? List and explain main motives of launching cyber
(08 Marks)

--- Content provided by FirstRanker.com ---

algorithm find the inverse of 12 modulo 79. (08 Marks)
OR
test attack to obtain the key used in the Vigenere cipher. (08 Marks)
m = 3 (block size = 3) with key k shown below:
text corresponding to the plaintext = (VOW)?

--- Content provided by FirstRanker.com ---

(ii) What is the plain text corresponding to the ciphertext = (TQX)? (08 Marks)
Module-2
3 a. List and explain RSA operations. (08 Marks)
b. The modulus in a toy implementation of RSA is 143
(i) What is the smallest value of a valid encryption key and the corresponding

--- Content provided by FirstRanker.com ---

decryption key?
(ii) For the computed encryption key and plaintext = 127, what is the corresponding
ciphertext? (08 Marks)
OR
4 a. In what way are the properties of the cryptographic hash ? the one way property and

--- Content provided by FirstRanker.com ---

collision resistance relevant to the security provided by the MAC? Explain. (08 Marks)
b. Consider the digital signature created using the Signer's private key operation but without
the hash function i.e., sign(m) = EA
pr
( m)

--- Content provided by FirstRanker.com ---

Demonstrate how a forged signature may be created using this definition of a digital
signature. (08 Marks)
Module-3
5 a. What do you mean key management? Explain the fields of an X.509 certificate. (06 Marks)
b. List and explain PKI Architectures. (06 Marks)

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c. Define Dictionary Attacks. Explain Attack types. (04 Marks)
OR
6 a. Design the Needham ? Schroeder protocol.
b. Define Kerberos. Explain Kerberos message sequence.
c. Explain SSL Record Layer Protocol.

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(06 Marks) ,
(05 Marks)
(05 Marks)
I of 2
15CS61

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Module-4
7 a. Explain how each key in 802.11i was derived and where it is used.
b. Define Firewall. List and explain main functions of a firewall.
c. Classify Intrusion Detection Systems based on their functionality.
(06 Marks)

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(06 Marks)
(04 Marks)
OR
8 a. What is the role of a Bloom Filter in packet logging? (04 Marks)
b. Define SOAP. Explain SOAP messages in HTTP packets. (08 Marks)

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c. Demonstrate WS-Trust relationship between entities involved in international trade.
(04 Marks)
Module-5
9 a. List and explain IT act aim and objectives.
b. Explain (i) Secure electronic record (ii) Secure digital signature

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c. List and explain Functions of a controller.
OR
10 a. List and explain offences with reference to computer system.
b. When network service providers not to be liable under IT Act? Explain.
c. What are miscellaneous provisions of IT Act? Explain.

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* *
(04 Marks)
(04 Marks)
(08 Marks)
*fr

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(06 Marks)
(04 Marks)
(06 Marks)

2 of 2

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