Download DU (University of Delhi) B-Tech (Bachelor of Technology) 7th Semester Information Security Question Paper
Your Roll No.
S]. No. of Q. Paper
Unique Paper Code
Name of the Course
Name of the Paper
Semester
Time : 3 Hours
cu. m
: 2341702
: B.Tech. Computer
Science
: CS-702 Information
Security
: VII
Maximum Marks : 75
Instructions for Candidates :
(a) Write your Roll No. on the top immediately
on receipt of
this question paper.
(b) Section - A is compulsory.
together.
(c) Attempt any 4 questions from Section - B.
Parts of a question must be answered
Section - A
1. (a) What is
vulnerability
i
the difference between
and exposure ? 2
P.T.O.
6132
(b)
(C)
(d)
(f)
(g)
(h)
(i)
De?ne linear congruence. Solve the
questions 3x + 4 5 (mod 13). 3
Find the multiplicative inverse of 132 in
Z . 3
l80
Differentiate between block ciphers and
stream ciphers. 3
Use af?ne cipher to encrypt the message
"Today is our- IS exam" with the key pair
(7.2). 2
Explain the concept of Fiestal Network. Also
prove that the mixer in Fiestal Cipher is
self-invertible. 5
Why does a round key generator need a
parity dr6p table ? 3
What is a honeypot ? How is it different
from a honeynet ? 2
Describe the legal issues in Security.
, z/ 2
(j)
(k)
(1)
(a)
(b)
6132
What would be the code word corresponding
to the message (1101). The generator
matrix, is given below : 2
g0 l l 0 l 0 0 0
G: g, = 0 l l 0 l 0 O
g2 1 l l 0 0 1 0
g3 1 0 l 0 0 0 1
Explain Man in the middle attack with a
suitable example. 3
Explain the Public key Infrastructure.
Section - B
Use the Playfair Cipher t0 encipher the
message "Information need to be secure".
The secret key can be made by filling the
matrix diagonally from top left corner.
Consider alphabets 'Y' and '2' together in
one cell of the matrix. 5
A Vigenere Cipher is a combination of m
additive ciphers. Justify with an example.
5
p 3 P.T.O.
6132 *
3.
(a) Consider a symmetric (8,4) code whose
parity ? check equations are.
6+4=10
V0=ul+u2+u3
Vl=u0+ul+u2
V2=uo+ul+ua
v3 = uO + u2 + ?3
Where 1.10 111 uz'and 113 are message digits
and Von V2 and V3 are parity-check digits.
Find the generator and parity-check
matrices for this code. Determine the
minimum distance of this code.
(b) Determine the weight distribution of the
18,4) linear code given In above problem.
Assume the transition probability of a BSC
be p = 102. Compute the probability ef an
undetected error of this code. I/
6132
If generator g = 2 and p = 11, use Dif?e?Hcllman
algorithm to solve the following for User A and
User B. 1+4+4+l
(a) Show that 2 is primitive root of 1 1.
(b) If A has public key 9 then what is A's private
key.
(c) If B has public key 3 then what is B's private
key.
((1) Calculate the shared secret key.
(3) Using the S?box below find out the result
of passing strings.
(i) 1 101 1 1
(ii) 001 100
??)1111;1
5 P.T.O.
6132 ' ?
S-Box Table i 6 1 32
0123 456789101112131415
7. Write a short notes on (any five) :
0 10000914 06031505 01 1312 07 11040208 : 2x5=10
1 13 07 00 09 03 04 0610 02 08 05 14 12 11 15 01 i (a) Honeypots
2 13 06 04 09 08 15 03 oo 11 01 02 12 05 1o 14 07 (b) DigitalSignaturc
3 01 10 13 oo 06 09 08 07 04 15 14 03 11 .05 02 12 (c) E-mailSecurity
(b) Brie?y describe the components of DES (d) Threats
including key generation. 7 (e) Transposition Cipher
. . . . neTime Pad
6. Brlefly explam Rabm Key Generatlon (0 0
Algorithm. Assume the private key pair is (23,
1]). Calculate the Cipher text if the plain text
is 24.Also calculate all four.possib1e plain text 1
for the corresponding cipher text. 10
f > .t
I.
// j
6 v
,r? 7 500
/
This post was last modified on 31 January 2020