Download AKTU B-Tech 8th Sem 2014-15 ECS 084 Cryptography And Network Security Question Paper

Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 8th Semester (Eight Semester) 2014-15 ECS 084 Cryptography And Network Security Question Paper

Printed Pages : 3
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PAPER 1D : 1 10854
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B. Tech.
(SEM. VIII) THEORY EXAMINATION, 2014-15
CRYPTOGRAPHY & NETWORK SECURITY
Time :,3 Hours] [Total Marks : 100
Note: 1. Attempt all questions.
2. A11 question carry equal marks.
3. Notations/Symbols/Abbreviations used have usual
meaning.
4. Make suitable assumption ,whereever required.
1. Attempt any four parts of following (5X4=20)
(a) Differentiate between the following terms clearly
(1) Cryptography and Steganography
(1i) Active attack and Passive attack
(Iii) Stream cipher and Block Cipher
(b) What is polyalphabetic cipher? Compare its strength
with monoalphabetic cipher.
(c) What do you understand by chosen plaintext attack?
Hill cipher is vulnerable to chosen plaintext attack?
comment.
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(d)
(e)
?(0
2 Attempt any four parts of following
(a)
(b)
?9
(d)
(e)
(f)
3 Attempt any two parts of the following
(a)
(b)
(C)
110854]
Draw block diagram of DES cipher showing size of
input/output of every blocks How important is swapping
step at the end of every round?
Give general format of a PGP message. Explain why
PGP generates a signature before applying compression?
Describe the encryption and decryption process of a
block cipher in Cipher Feedback(CFB) mode.
(5x4-20)
Describe RSA algorithm. Whether RSA encryption and
decryption works or not if message m has common
factor with modulus n of the scheme.
De?ne group. What is multiplication in use ?
Give comparison of ABS Cipher to the DES cipher.
State Chinese Remainder theorem. Use it to solve the
following simultaneous congruence x54 mod 7,XE4
mod 13,XE5 mod 12.
State and prove Euler's theorem. Compute the value
of Euler's totient function for 300.
State and prove Fermat's theorem.
(10x2=20)
Write the signature generation and veri?cation process
ofdigital Walgo?tlm ofDigital signaquesmndard.
Discuss at least one approach that can be used to launch
a bixthday attack on message authentication code.
Draw a block level diagram to depict the structure of
one round of DES. Prove that if plaintext block and
encryption key are complemented then resulting ciphenext
block of DES encryption is also complemented.
2 [ Contd...
(a)
(b)
(C) '
5 Attempt any two parts of the following
(a)
(b)
(C)
110854]
Attempt any two parts of the following
(10x2=20)
Explain the concept of dual signature in context of
Secure Electronic Transactim(SET).Brie?y describe the
sequence of events that are required for a SET
transaction.
Describe the approaches used for intrusion detection.
What is kexboros? What requirements were de?ned for
Kerberos? bescribe the sequence of message exchanges
of kerberos Version 4.
(10x2=20)
What is pelmutation cipher? Whether penmxtation ciphers
are susceptible to the statistical analysis or not? Discuss
Encxyption key in a penmnation cipher is (3,7,2,6,_ 1,8,5)
Write short notes on any two
(1) IP Secun'tyaP See)
(ii) Secure Socket Layer
(iii) Malicious Software
What is SIMIME? Why is it used? What are the main
functions S/MJME provides?
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