MCQOPTIONS
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MCQOPTIONS
This section includes 141 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.
| 101. |
TEA cipher uses which of the following structure? |
| A. | standard cipher structure |
| B. | pseudo random structure |
| C. | feistel structure |
| D. | block structure |
| Answer» D. block structure | |
| 102. |
For some number b, (1⁄b)⁻ⁿ is equal to _________ |
| A. | -bⁿ |
| B. | nᵇ |
| C. | bⁿ |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 103. |
Radix complement can be obtained fromdiminished radix’s complement by _________ |
| A. | Adding one to diminished radox’s complement |
| B. | Subtracting one to diminished radox’s complement |
| C. | Both are same things |
| D. | None of the mentioned |
| Answer» B. Subtracting one to diminished radox’s complement | |
| 104. |
The ROT13 caesar cipher system has an offset of ___________ |
| A. | 13 |
| B. | 45 |
| C. | 71 |
| D. | 37 |
| Answer» B. 45 | |
| 105. |
If there are 2⁵⁶ cipher texts per plain text and a total of 2¹⁸ plaintexts of length 18 exists. Then determine the number of distinct ciphertexts? |
| A. | 761 |
| B. | 2⁷⁴ |
| C. | 186 |
| D. | 2⁸⁹ |
| Answer» C. 186 | |
| 106. |
In which of the following systems, encryption slower than decryption? |
| A. | elliptic curve cryptography |
| B. | parabolic curve cryptography |
| C. | symmetric cryptography |
| D. | antisymmetric cryptography |
| Answer» C. symmetric cryptography | |
| 107. |
How many bits of message does the Secure Hash Algorithm produce? |
| A. | 160 bits |
| B. | 1035 bits |
| C. | 621 bits |
| D. | 3761 bits |
| Answer» B. 1035 bits | |
| 108. |
How many combinations of keys can be constructed from a 72 ciphertext stream cipher? |
| A. | 4271 |
| B. | 7345 |
| C. | 3291 |
| D. | 2556 |
| Answer» E. | |
| 109. |
In a transposition cipher, the plaintext is constructed by the ________ of the ciphertext. |
| A. | permutation |
| B. | combination |
| C. | sequence |
| D. | series |
| Answer» B. combination | |
| 110. |
In which cipher each letter of the plaintext is substituted by any other letter to form the cipher message? |
| A. | Shift cipher |
| B. | DES encryption |
| C. | Block cipher |
| D. | AES encryption |
| Answer» B. DES encryption | |
| 111. |
Is 7, 8, 9, 11 are pairwise relatively prime. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 112. |
There are 67 people in a company where they are using secret key encryption and decryption system for privacy purpose. Determine the number of secret keys required for this purpose? |
| A. | 887 |
| B. | 6529 |
| C. | 2211 |
| D. | 834 |
| Answer» D. 834 | |
| 113. |
One’s complement of a number x is y, then one’s complement of y is? |
| A. | y |
| B. | x |
| C. | x + y |
| D. | None of the mentioned |
| Answer» C. x + y | |
| 114. |
If there is a unique prime number p₁ then a finite field F has the property of ______________ |
| A. | p₁x = 0 for all x in F |
| B. | f(x) = f(xp₁) for all x in F |
| C. | p₁ = y for all y in F |
| D. | xy + p₁ for all x, y in F |
| Answer» B. f(x) = f(xp₁) for all x in F | |
| 115. |
Which positive integer less than 21 are relatively prime to 21? |
| A. | 18 |
| B. | 19 |
| C. | 21 |
| D. | 24 |
| Answer» C. 21 | |
| 116. |
LCM(a, b) is equals to _________ |
| A. | ab/(GCD(a, b)) |
| B. | (a+b)/(GCD(a, b)) |
| C. | (GCD(a, b))/ab |
| D. | none of the mentioned |
| Answer» B. (a+b)/(GCD(a, b)) | |
| 117. |
How many bits are there for random bits and error detection bits in the case of DES block ciphers? |
| A. | 72, 1024 |
| B. | 56, 8 |
| C. | 104, 45 |
| D. | 32, 198 |
| Answer» C. 104, 45 | |
| 118. |
The inverse of 3 modulo 7 is? |
| A. | -1 |
| B. | -2 |
| C. | -3 |
| D. | -4 |
| Answer» C. -3 | |
| 119. |
A multiplicative monoid defines the property of exponentiation with ________ |
| A. | integer exponents |
| B. | fractional exponents |
| C. | rational exponents |
| D. | negative integer exponents |
| Answer» B. fractional exponents | |
| 120. |
______ uses the concept of pseudo-random sequence. |
| A. | Stream cipher |
| B. | DES encryption |
| C. | Caesar cipher |
| D. | Block cipher |
| Answer» B. DES encryption | |
| 121. |
If LCM of two number is 14 and GCD is 1 then the product of two numbers is? |
| A. | 14 |
| B. | 15 |
| C. | 7 |
| D. | 49 |
| Answer» B. 15 | |
| 122. |
The LCM of two number 1, b(integer) are _________ |
| A. | b + 2 |
| B. | 1 |
| C. | b |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 123. |
If a, b are two distinct prime number than a highest common factor of a, b is ___________ |
| A. | 2 |
| B. | 0 |
| C. | 1 |
| D. | ab |
| Answer» D. ab | |
| 124. |
Difference of two distinct prime numbers is? |
| A. | Odd and prime |
| B. | Even and composite |
| C. | None of the mentioned |
| D. | All of the mentioned |
| Answer» D. All of the mentioned | |
| 125. |
If a, b, c, d are distinct prime numbers with an as smallest prime then a * b * c * d is a ___________ |
| A. | Odd number |
| B. | Even number |
| C. | Prime number |
| D. | None of the mentioned |
| Answer» C. Prime number | |
| 126. |
3 is the smallest prime number possible. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 127. |
Sum of two different prime number is a ____________ |
| A. | Prime number |
| B. | Composite number |
| C. | Either Prime or Composite |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 128. |
There are finite number of prime numbers. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 129. |
How many prime numbers are there between 1 to 20? |
| A. | 5 |
| B. | 6 |
| C. | 7 |
| D. | None of the mentioned |
| Answer» E. | |
| 130. |
The number of factors of prime numbers are ___________ |
| A. | 2 |
| B. | 3 |
| C. | Depends on the prime number |
| D. | None of the mentioned |
| Answer» B. 3 | |
| 131. |
What is the number ‘ 1’? |
| A. | Prime number |
| B. | Composite number |
| C. | Neither Prime nor Composite |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 132. |
All prime numbers are odd. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 133. |
FIND_THE_SOLUTION_OF_X2‚ÄÖ√Ñ√∂‚ÀÖ¬¢¬¨‚ÀÛ_16_MOD_23?$# |
| A. | x = 6 and 17 |
| B. | x = 4 and 19 |
| C. | x = 11 and 12 |
| D. | x = 7 and 16 |
| Answer» C. x = 11 and 12 | |
| 134. |
Find the solution of x2≡ 2 mod 11 has a solution.$# |
| A. | True |
| B. | False |
| Answer» C. | |
| 135. |
Find_the_solution_of_x^2≡3_mod_23$# |
| A. | x≡±16 mod 23 |
| B. | x≡±13 mod 23 |
| C. | x≡±22 mod 23 |
| D. | x≡±7 mod 23 |
| Answer» B. x‚Äö√Ñ√∂‚àö¬¢¬¨‚àû¬¨¬®¬¨¬±13 mod 23 | |
| 136. |
If we use exponentiation to encrypt/decrypt, the adversary can use logarithm to attack and this method is very efficient. |
| A. | True |
| B. | False |
| Answer» C. | |
| 137. |
Find the solution of x2≡ 15 mod 23 has a solution?# |
| A. | True |
| B. | False |
| Answer» C. | |
| 138. |
Euler’s Criterion can find the solution to x2 ≡ a (mod n).$ |
| A. | True |
| B. | False |
| Answer» C. | |
| 139. |
In Zp* with (p-1) elements exactly: |
| A. | /2 elements are QR and |
| B. | /2 elements are QNR. |
| C. | True |
| D. | False |
| Answer» B. /2 elements are QNR. | |
| 140. |
Find the solution of x2≡ 3 mod 11$ |
| A. | x ≡ -9 mod 11 and x≡ 9 mod 11 |
| B. | x ≡ 9 mod 11 |
| C. | No Solution |
| D. | x ≡ 5 mod 11 and x ≡ 6 mod 11 |
| Answer» E. | |
| 141. |
Equations have either no solution or exactly three incongruent solutions |
| A. | True |
| B. | False |
| Answer» C. | |