Explore topic-wise MCQs in Cryptography and Network Security.

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.

51.

8 is quardratic residue of 11.

A. True
B. False
C. May be True or False
D. Can't say
Answer» C. May be True or False
52.

What is the block size of blowfish block cipher?

A. 64 bits
B. 128 bits
C. 1043 bits
D. 10 bits
Answer» B. 128 bits
53.

Decimal equivalent of binary number 1010 is?

A. 11
B. A
C. 10
D. None of the mentioned
Answer» D. None of the mentioned
54.

The integer 2821 is a Carmichael number.

A. True
B. False
C. May be True or False
D. Can't say
Answer» B. False
55.

Which of the number is not allowed in Binary representation of a number?

A. 0
B. 1
C. 2
D. None of the mentioned
Answer» D. None of the mentioned
56.

The HCF of two prime numbers a and b is _________

A. a⁄b
B. ab
C. a + b
D. 1
Answer» E.
57.

If 0ᵃ is not equal to zero then which of the values a cannot take _________

A. 1
B. 2
C. -1
D. 0
Answer» E.
58.

The solution of the linear congruence 4x = 5(mod 9) is?

A. 6(mod 9)
B. 8(mod 9)
C. 9(mod 9)
D. 10(mod 9)
Answer» C. 9(mod 9)
59.

The value of 5²⁰⁰³ mod 7 is?

A. 3
B. 4
C. 8
D. 9
Answer» B. 4
60.

_______ is an example of asymmetric ciphers.

A. Block cipher
B. RSA encryption
C. AES encryption
D. Advanced cryptology
Answer» C. AES encryption
61.

Determine the value of x, where y = 7, e = 12 and n = 566 using modular exponentiation method (x ≡ yᵉ (mod n)).

A. 735
B. 321
C. 872
D. 487
Answer» E.
62.

LCM of 6, 10 is?

A. 60
B. 30
C. 10
D. 6
Answer» C. 10
63.

If a, b are integers such that a > b then lcm(a, b) lies in _________

A. a>lcm(a, b)>b
B. a>b>lcm(a, b)
C. lcm(a, b)>=a>b
D. none of the mentioned
Answer» D. none of the mentioned
64.

The HCF of two number 1, b(integer) are _________

A. b + 2
B. 1
C. b
D. None of the mentioned
Answer» C. b
65.

A Least Common Multiple of a, b is defined as __________

A. It is the smallest integer divisible by both a and b
B. It is the greatest integer divisible by both a and b
C. It is the sum of the number a and b
D. None of the mentioned
Answer» B. It is the greatest integer divisible by both a and b
66.

Which of the following algorithms has better computational complexity than standard division algorithms?

A. Montgomery algorithm
B. Classical modular exponentiation algorithm
C. ASM algorithm
D. FSM algorithm
Answer» C. ASM algorithm
67.

The least common multiple of 41.42 and 42.41 is ____________

A. 42
B. 41
C. 84
D. 41.42
Answer» E.
68.

9’s complement of 23456 is?

A. 87654
B. 76543
C. 12345
D. none of the mentioned
Answer» C. 12345
69.

Evaluate the expression 6359 mod 320.

A. 681
B. 811
C. 3781
D. 279
Answer» E.
70.

If a number is 2² x 3¹ x 5⁰ and b is 2² x 3¹ x 5¹ then hcf of a, b is?

A. 2² x 3¹ x 5¹
B. 2² x 3² x 5²
C. 2¹ x 3¹ x 5⁰
D. 2² x 3² x 5⁰
Answer» D. 2² x 3² x 5⁰
71.

Suppose that there are two primes, p₁ = 229 and p₂ = 61. Find the value of z and Φ.

A. 13969, 13680
B. 5853, 23452
C. 7793, 34565
D. 17146, 69262
Answer» B. 5853, 23452
72.

_______ are used as the base of the Public Key Infrastructure.

A. SSL certificates
B. TLS certificates
C. X.509 certificates
D. HAS certificates
Answer» D. HAS certificates
73.

________ can decrypt traffic to make it available to all other network security functions such as web proxies.

A. SSL visibility appliances
B. RSA appliances
C. Rodriguez cipher system
D. Standard cipher system
Answer» B. RSA appliances
74.

If ab = 1, where a and b are real numbers then?

A. a = b⁻¹
B. b = a
C. a = b = 2
D. none of the mentioned
Answer» B. b = a
75.

The linear combination of gcd(252, 198) = 18 is?

A. 252*4 – 198*5
B. 252*5 – 198*4
C. 252*5 – 198*2
D. 252*4 – 198*4
Answer» B. 252*5 – 198*4
76.

What are the steps in the Feistel function?

A. expansion, mixing, substitution, permutation
B. extract, transform, load
C. extract, load, transform
D. expansion, divide, mixing, permutation
Answer» B. extract, transform, load
77.

Which of the following methods uses the concept that exponentiation is computationally inexpensive in the finite field?

A. Diffie-HEllman key exchange
B. RSA key exchange
C. Arithmetic key exchange
D. FSM method
Answer» B. RSA key exchange
78.

Suppose in order to get a message across enemy lines, we need to choose an initial secret key say, 100110. What will be the decrypted cipher when the original message is 010010011.

A. 110100
B. 1001011
C. 0011010
D. 011011
Answer» B. 1001011
79.

In cryptography system, the value of z in x ≡ zᵉ (mod m) should be at least ______

A. 1024 bits
B. 1GB
C. 596 bits
D. 54 Bytes
Answer» B. 1GB
80.

The greatest common divisor of 0 and 5 is ___________

A. 0
B. 1
C. 2
D. 5
Answer» C. 2
81.

According to congruence relation, find the remainder of 56 mod 24.

A. 10
B. 12
C. 6
D. 4
Answer» D. 4
82.

If a is a real number, then a⁰ is defined as _________

A. 0
B. a
C. 1
D. -1
Answer» B. a
83.

The linear combination of gcd(117, 213) = 3 can be written as _________

A. 11*213 + (-20)*117
B. 10*213 + (-20)*117
C. 11*117 + (-20)*213
D. 20*213 + (-25)*117
Answer» B. 10*213 + (-20)*117
84.

Using RSA algorithm what is the value of cipher test c if the plain text e = 7 and P = 5, q = 16 & n = 832. Determine the Euler’s totient function for the plain text?

A. 47
B. 584
C. 428
D. 60
Answer» E.
85.

4 is quardratic residue of 7.

A. True
B. False
C. May be True or False
D. Can't say
Answer» B. False
86.

In encryption, which of the following is the best text encoding technique?

A. ASCII encoding
B. Hex-encoding
C. Unicode technique
D. Base64 encoding
Answer» D. Base64 encoding
87.

Octal number may contain digits from 1 to 8.

A. True
B. False
C. May be True or False
D. Can't say
Answer» C. May be True or False
88.

The product of two numbers are 12 and there LCM is 6 then HCF is?

A. 12
B. 2
C. 6
D. None of the mentioned
Answer» C. 6
89.

Let A’s public key is n=6, 736, 180, 7817, 961, 456, 267 and e = 5 and B sends the ciphertext. c = 456, 871, 122, 391, 882, 538 to A. Determine B’s message in numeric format?

A. 235813
B. 57971.89
C. 770190.04
D. 687651.9
Answer» D. 687651.9
90.

F in hexadecimal representation is equivalent to 9 in decimal.

A. True
B. False
C. May be True or False
D. Can't say
Answer» C. May be True or False
91.

The Fermat’s little theorem for odd prime p and coprime number a is?

A. aᵖ⁻¹ ≡ 1 (mod p)
B. aᵖ⁻¹ ≡ 7 (mod p)
C. aᵖ⁽²⁾⁻¹ ≡ 1 (mod p)
D. none of the mentioned
Answer» B. aᵖ⁻¹ ≡ 7 (mod p)
92.

HCF of 6, 10 is?

A. 60
B. 30
C. 10
D. 2
Answer» E.
93.

If there exist an integer x such that x² ≡ q (mod n). then q is called ______________

A. Quadratic Residue
B. Linear Residue
C. Pseudoprime
D. None of the mentioned
Answer» B. Linear Residue
94.

The inverse of 7 modulo 26 is?

A. 12
B. 14
C. 15
D. 20
Answer» D. 20
95.

There is no secret key in case of ____________

A. Symmetric ciphers
B. Asymmetric ciphers
C. RSA encryption
D. Alpha-numeric cryptography
Answer» B. Asymmetric ciphers
96.

The greatest common divisor of 3¹³.5¹⁷ and 2¹².3⁵ is __________

A. 3⁰
B.
C.
D. 3⁵
Answer» E.
97.

The linear combination of gcd(10, 11) = 1 can be written as _________

A. (-1)*10 + 1*11
B. (-2)*10 + 2*11
C. 1*10 + (-1)*11
D. (-1)*10 + 2*11
Answer» B. (-2)*10 + 2*11
98.

A Highest Common Factor of a, b is defined as ___________

A. It is the smallest integer divisible by both a and b
B. It is the greatest integer divisor of both a and b
C. It is the sum of the number a and b
D. None of the mentioned
Answer» C. It is the sum of the number a and b
99.

Pseudo prime are classified based on property which they satisfy, which of the following are classes of pseudoprimes?

A. Fermat pseudoprime
B. Fibonacci pseudoprime
C. Euler pseudoprime
D. All of the mentioned
Answer» E.
100.

What is the one’s complement of the number 1010110?

A. 1111111
B. 0101001
C. 1100110
D. None of the mentioned
Answer» C. 1100110