Explore topic-wise MCQs in Cryptography and Network Security.

This section includes 16 Mcqs, each offering curated multiple-choice questions to sharpen your Cryptography and Network Security knowledge and support exam preparation. Choose a topic below to get started.

1.

A symmetric cipher system has an IC of 0.041. What is the length of the key ‘m’?

A. 1
B. 3
C. 2
D. 5
Answer» E.
Discussion
2.

Consider the cipher text message with relative frequencies: 4 0 10 25 5 32 24 15 6 11 5 5 1 2 6 6 15 19 10 0 6 28 8 2 3 2The Index of Coincidence isa) 0.065b) 0.048c) 0.067d) 0.042 The Index of Coincidence is –

A. 0.065b) 0.048c) 0.067d) 0.042 The Index of Coincidence is –a) 0.065
B. 0.048c) 0.067d) 0.042 The Index of Coincidence is –a) 0.065b) 0.048
C. 0.067d) 0.042 The Index of Coincidence is –a) 0.065b) 0.048c) 0.067
D. 0.042 The Index of Coincidence is –a) 0.065b) 0.048c) 0.067d) 0.044View Answer
Answer» D. 0.042 The Index of Coincidence is –a) 0.065b) 0.048c) 0.067d) 0.044View Answer
Discussion
3.

If all letters have the same chance of being chosen, the IC is approximately

A. 0.065
B. 0.035
C. 0.048
D. 0.038
Answer» E.
Discussion
4.

The Index of Coincidence for English language is approximately

A. 0.068
B. 0.038
C. 0.065
D. 0.048
Answer» D. 0.048
Discussion
5.

On Encrypting “cryptography” using Vignere Cipher System using the keyword “LUCKY” we get cipher text

A. nlazeiibljji
B. nlazeiibljii
C. olaaeiibljki
D. mlaaeiibljki
Answer» B. nlazeiibljii
Discussion
6.

On Encrypting “thepepsiisintherefrigerator” using Vignere Cipher System using the keyword “HUMOR” we get cipher text-

A. abqdnwewuwjphfvrrtrfznsdokvl
B. abqdvmwuwjphfvvyyrfznydokvl
C. tbqyrvmwuwjphfvvyyrfznydokvl
D. baiuvmwuwjphfoeiyrfznydokvl
Answer» C. tbqyrvmwuwjphfvvyyrfznydokvl
Discussion
7.

Use Caesar’s Cipher to decipher the followingHQFUBSWHG WHAW

A. ABANDONED LOCK
B. ENCRYPTED TEXT
C. ABANDONED TEXT
D. ENCRYPTED LOCK
Answer» C. ABANDONED TEXT
Discussion
8.

IF_ALL_LETTERS_HAVE_THE_SAME_CHANCE_OF_BEING_CHOSEN,_THE_IC_IS_APPROXIMATELY?$

A. 0.065
B. 0.035
C. 0.048
D. 0.038
Answer» E.
Discussion
9.

The Index of Coincidence for English language is approximatel?

A. 0.068
B. 0.038
C. 0.065
D. 0.048
Answer» D. 0.048
Discussion
10.

On Encrypting “cryptography” using Vignere Cipher System using the keyword “LUCKY” we get cipher text$

A. nlazeiibljji
B. nlazeiibljii
C. olaaeiibljki
D. mlaaeiibljki
Answer» B. nlazeiibljii
Discussion
11.

On Encrypting “thepepsiisintherefrigerator” using Vignere Cipher System using the keyword “HUMOR” we get cipher text-$

A. abqdnwewuwjphfvrrtrfznsdokvl
B. abqdvmwuwjphfvvyyrfznydokvl
C. tbqyrvmwuwjphfvvyyrfznydokvl
D. baiuvmwuwjphfoeiyrfznydokvl
Answer» C. tbqyrvmwuwjphfvvyyrfznydokvl
Discussion
12.

Choose from among the following cipher systems, from best to the worst, with respect to ease of decryption using frequency analysis.

A. Random Polyalphabetic, Plaintext, Playfair
B. Random Polyalphabetic, Playfair, Vignere
C. Random Polyalphabetic, Vignere, Playfair, Plaintext
D. Random Polyalphabetic, Plaintext, Beaufort, Playfair
Answer» D. Random Polyalphabetic, Plaintext, Beaufort, Playfair
Discussion
13.

Which are the most frequently found letters in the English language ?

A. e,a
B. e,o
C. e,t
D. e,i
Answer» D. e,i
Discussion
14.

Monoalphabetic ciphers are stronger than Polyalphabetic ciphers because frequency analysis is tougher on the former.

A. True
B. False
Answer» C.
Discussion
15.

Caesar Cipher is an example of

A. Poly-alphabetic Cipher
B. Mono-alphabetic Cipher
C. Multi-alphabetic Cipher
D. Bi-alphabetic Cipher
Answer» C. Multi-alphabetic Cipher
Discussion
16.

Use Caesar’s Cipher to decipher the following

A.
B. ABANDONED LOCK
C. ENCRYPTED TEXT
Answer» C. ENCRYPTED TEXT
Discussion