Deck 2: Cryptography and Encryption

Question 1

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 1

random polyalphabetic , vignere , playfair , plaintext

Question 2

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

A)abqdnwewuwjphfvrrtrfzn sdokvl
B)abqdvmwuwjphfvvyyrf znydokvl
C)tbqyrvmwuwjphfvvyy rfznydokvl
D)baiuvmwuwjphfoeiyrf znydokvl

Answer 2

abqdvmwuwjphfvvyyrf znydokvl

Question 3

. Rail Fence Technique is an example of

A)substitution
B)transposition
C)product cipher
D)ceaser cipher

Answer 3

transposition

Question 4

Public key encryption is advantageous over Symmetric key Cryptography because of

A)speed
B)space
C)key exchange
D)key length

Question 5

The sub key length at each round of DES is

A)32
B)56
C)48
D)64

Question 6

Which one is the strong attack mechanism?

A)chosen plaintext attack
B)chosen cipher text
C)brute force attack
D)man in the middle attack

Question 7

Interception is an attack on

A)availability
B)confidentiality
C)integrity
D)authenticity

Question 8

Chosen cipher text attack is based on

A)cryptanalysis
B)cryptography
C)encryption
D)decryption

Question 9

The process of writing the text as rows and read it as columns is known as

A)vernam cipher
B)ceaser cipher
C)transposition columnar cipher
D)homophonic substitution cipher

Question 10

Biometric authentication works on the basis of

A)human characteristics
B)passwords
C)smart cards
D)pin

Question 11

Which layer filters the proxy firewall?

A)application
B)network
C)transport
D)none of the above

Question 12

Encryption Strength is based on

A)strength of algorithm
B)secrecy of key
C)length of key
D)all of the above

Question 13

GCD(a,b) = GCD(b,a mod b)

A)true
B)false
C)cannot be determined
D)none

Question 14

All groups satisfy properties

A)g-i to g-v
B)g-i to g-iv
C)g-i to r-v
D)r-i to r-v

Question 15

An Abelian Group satisfies the properties

A)g-i to g-v
B)g-i to g-iv
C)g-i to r-v
D)r-i to r-v

Question 16

A Ring satisfies the properties

A)r-i to r-v
B)g-i to g-iv
C)g-i to r-v
D)g-i to r-iii

Question 17

A Ring is said to be commutative if it also satisfies the property

A)r-vi
B)r-v
C)r-vii
D)r-iv

Question 18

An 'Integral Domain' satisfies the properties

A)g-i to g-iii
B)g-i to r-v
C)g-i to r-vi
D)g-i to r-iii

Question 19

Does the set of residue classes (mod 3) form a group with respect to modular addition?

A)yes
B)no
C)can\t say
D)insufficient data

Question 20

For the group Sn of all permutations of n distinct symbols, what is the number of elements in Sn?

A)n
B)n-1
C)2n
D)n!

Question 21

a(b+c) = ac+bc is the representation for which property?

A)g-ii
B)g-iii
C)r-ii
D)r-iii

Question 22

a.(b.c) = (a.b).c is the representation for which property?

A)g-ii
B)g-iii
C)r-ii
D)r-iii

Question 23

AES uses a ________bit block size and a key size of__________bits.

A)128; 128 or 256
B)64; 128 or 192
C)256; 128, 192, or 256
D)128; 128, 192, or 256

Question 24

Like DES, AES also uses Feistel Structure.

A)true
B)false
C)cannot be determined
D)none

Question 25

Which one of the following is not a cryptographic algorithm?

A)jupiter
B)blowfish
C)serpent
D)none