MCQOPTIONS
Saved Bookmarks
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.
| 1. |
Find the solution of x2≡7 mod 19 |
| A. | x≡±16 mod 23 |
| B. | x≡±11 mod 23 |
| C. | x≡±14 mod 23 |
| D. | x≡±7 mod 23 |
| Answer» C. x≡±14 mod 23 | |
| 2. |
Find the solution of x2≡ 2 mod 11 has a solution. |
| A. | True |
| B. | False |
| Answer» C. | |
| 3. |
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≡±13 mod 23 | |
| 4. |
Find the solution of x2≡ 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 | |
| 5. |
Find the solution of x2≡ 15 mod 23 has a solution. |
| A. | True |
| B. | False |
| Answer» C. | |
| 6. |
Euler’s Criterion can find the solution to x2 ≡ a (mod n). |
| A. | True |
| B. | False |
| Answer» C. | |
| 7. |
Find the set of quadratic residues in the set –Z13* = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,11,12} |
| A. | QR { 1, 2, 4,5, 10, 12} |
| B. | QR { 2, 4, 5, 9, 11, 12} |
| C. | QR { 1, 2, 4,5,10, 11} |
| D. | QR { 1, 3, 4, 9, 10, 12} |
| Answer» E. | |
| 8. |
In Zp* with (p-1) elements exactly:(p – 1)/2 elements are QR and(p – 1)/2 elements are QNR. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 9. |
Find the set of quadratic residues in the set –Z11* = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10} |
| A. | QR set = {1, 2, 4, 5, 9} of Z11* |
| B. | QR set = {1, 3, 6, 5, 9} of Z11* |
| C. | QR set = {1, 3, 4, 9,10} of Z11* |
| D. | QR set = {1, 3, 4, 5, 9} of Z11* |
| Answer» E. | |
| 10. |
Find the solution of x2≡ 2 mod 11 |
| A. | No Solution |
| B. | x ≡ 9 mod 11 |
| C. | x ≡ 4 mod 11 |
| D. | x ≡ 4 mod 11 and x ≡ 7 mod 11 |
| Answer» B. x ≡ 9 mod 11 | |
| 11. |
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. | |
| 12. |
Apply Chinese Remainder theorem to solve x = 3 (mod9), x = 7 (mod13). the common solution is |
| A. | x = 107 (mod 117) |
| B. | x = 103 (mod 117) |
| C. | x = 111 (mod 117) |
| D. | x = 105 (mod 117) |
| Answer» D. x = 105 (mod 117) | |
| 13. |
How many bytes of the secret key is generated using Diffie-Hellman encryption/decryption scheme? |
| A. | 256 |
| B. | 871 |
| C. | 1024 |
| D. | 962 |
| Answer» B. 871 | |
| 14. |
The default key size of RC2 Feistel cipher is _______ |
| A. | 64GB |
| B. | 64 bits |
| C. | 64 bytes |
| D. | 64KB |
| Answer» D. 64KB | |
| 15. |
To encrypt a message _______ is used on the character’s positions. |
| A. | boolean algebra |
| B. | bijective function |
| C. | inverse function |
| D. | surjective function |
| Answer» C. inverse function | |
| 16. |
What is the block size of RC6 Feistel block cipher? |
| A. | 5013 bits |
| B. | 128 bits |
| C. | 596 bits |
| D. | 1768 bits |
| Answer» C. 596 bits | |
| 17. |
8 is quardratic residue of 17. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 18. |
If LCM of two number is 10 and GCD is 5 then the product of two numbers is? |
| A. | 45 |
| B. | 50 |
| C. | 7 |
| D. | 49 |
| Answer» C. 7 | |
| 19. |
If a,b are integers such that a > b then hcf(a, b) lies in _________ |
| A. | a> hcf(a, b)>b |
| B. | a>b> = hcf(a, b) |
| C. | hcf(a, b)> = a>b |
| D. | None of the mentioned |
| Answer» C. hcf(a, b)> = a>b | |
| 20. |
If a number is 2² x 3¹ x 5⁰ and b is 2¹ x 3¹ x 5¹ then lcm of a, b is? |
| A. | 2² x 3¹ x 5¹ |
| B. | 2² x 3² x 5² |
| C. | 2³ x 3¹ x 5⁰ |
| D. | 2² x 3² x 5⁰ |
| Answer» B. 2² x 3² x 5² | |
| 21. |
The public key of given user, in an RSA encryption system is e = 57 and n = 3901. What is the value of Euler’s totient function ϕ(n) for calculating the private key of the user? |
| A. | 4369 |
| B. | 3772 |
| C. | 871 |
| D. | 7892 |
| Answer» C. 871 | |
| 22. |
What is pseudo prime number? |
| A. | is a probable prime and is not a prime number |
| B. | is a prime number |
| C. | does not share any property with prime number |
| D. | none of the mentioned |
| Answer» B. is a prime number | |
| 23. |
The product of two numbers are 12 and their Greatest common divisor is 2 then LCM is? |
| A. | 12 |
| B. | 2 |
| C. | 6 |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 24. |
The lcm of 3 and 21 is ________ if gcd(3,21)=3. |
| A. | 3 |
| B. | 12 |
| C. | 21 |
| D. | 42 |
| Answer» D. 42 | |
| 25. |
In a public key system, the cipher text received is C = 10 if RSA encryption used with a public key(e = 11, n = 77) to deduce the plain text. Determine the value of ϕ(n)? |
| A. | 49 |
| B. | 60 |
| C. | 123 |
| D. | 70 |
| Answer» C. 123 | |
| 26. |
5 is quardratic non-residue of 7. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 27. |
HCF(a, b) is equals to _________ |
| A. | ab/(LCM(a, b)) |
| B. | (a + b)/(LCM(a, b)) |
| C. | (LCM(a, b))/ab |
| D. | None of the mentioned |
| Answer» B. (a + b)/(LCM(a, b)) | |
| 28. |
One’s complement in binary is defined as _________ |
| A. | Flipping each binary bit |
| B. | Adding one to the binary number |
| C. | Flipping only bits having zero in it |
| D. | None of the mentioned |
| Answer» B. Adding one to the binary number | |
| 29. |
The two’s complement of 101110100 is represented as? |
| A. | 010001100 |
| B. | 101110101 |
| C. | 010001100 |
| D. | None of the mentioned |
| Answer» B. 101110101 | |
| 30. |
Nine’s complement of a number is formed by _________ |
| A. | replacing each digit by 9 minus that digit |
| B. | replacing each digit by 1plus that digit |
| C. | replacing each digit by 8 minus that digit |
| D. | None of the mentioned |
| Answer» B. replacing each digit by 1plus that digit | |
| 31. |
Decimal equivalent of one’s complement of 11111001 is? |
| A. | 5 |
| B. | 6 |
| C. | 4 |
| D. | 10 |
| Answer» C. 4 | |
| 32. |
If 2ᵃ⁻ᵇ = 1 then the value of a-b is equal to _________ |
| A. | 1 |
| B. | 0 |
| C. | 2 |
| D. | none of the mentioned |
| Answer» C. 2 | |
| 33. |
The inverse of 19 modulo 141 is? |
| A. | 50 |
| B. | 51 |
| C. | 54 |
| D. | 52 |
| Answer» E. | |
| 34. |
The integer 561 is a Carmichael number. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» B. False | |
| 35. |
For some number a, b and c, cᵃ/cᵇ is equal to _________ |
| A. | cᵃ⁻ᵇ |
| B. | cᵃ⁺ᵇ |
| C. | c |
| D. | None of the mentioned |
| Answer» B. cᵃ⁺ᵇ | |
| 36. |
For some number a, b and c, cᵃ x cᵇ is equal to _________ |
| A. | cᵃ⁻ᵇ |
| B. | cᵃ⁺ᵇ |
| C. | c |
| D. | none of the mentioned |
| Answer» C. c | |
| 37. |
Decimal 13 in base 8 can be represented as _________ |
| A. | 15 |
| B. | 12 |
| C. | 22 |
| D. | None of the mentioned |
| Answer» B. 12 | |
| 38. |
Hexadecimal number equivalent of decimal 10 is? |
| A. | 10 |
| B. | A |
| C. | F |
| D. | None of the mentioned |
| Answer» C. F | |
| 39. |
The binary number 100110 in octal is represented by _______________ |
| A. | 45 |
| B. | 10012 |
| C. | 46 |
| D. | 58 |
| Answer» D. 58 | |
| 40. |
Which of the number is not allowed in Octal representation of a number? |
| A. | 0 |
| B. | 4 |
| C. | 8 |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 41. |
For some base r, the digits which are allowed in its representation are? |
| A. | Digits from 1 to r |
| B. | Digits from 0 to r-1 |
| C. | Digits from 1 to r-1 |
| D. | None of the mentioned |
| Answer» C. Digits from 1 to r-1 | |
| 42. |
The time complexity to perform the modular exponentiation of a ≡ cᵍ (mod m). |
| A. | O(m+a) |
| B. | O(a*g) |
| C. | O(gm) |
| D. | O(g) |
| Answer» E. | |
| 43. |
If the multiplicative inverse of “53 modulo 21” exists, then which of the following is true? |
| A. | GCD(53,21) = 1 |
| B. | GCD(53,21) = 29 |
| C. | GCD(53,21) = 53 |
| D. | GCD(53,21) = 12 |
| Answer» B. GCD(53,21) = 29 | |
| 44. |
What type of algorithm does AES encryption use? |
| A. | Stream cipher |
| B. | Symmetric block cipher |
| C. | Asymmetric caesar cipher |
| D. | DES encryption |
| Answer» C. Asymmetric caesar cipher | |
| 45. |
If there exist no integer x such that x² ≡ q (mod n). then q is called __________ |
| A. | Quadratic Residue |
| B. | Quadratic Nonresidue |
| C. | Pseudoprime |
| D. | None of the mentioned |
| Answer» C. Pseudoprime | |
| 46. |
The lcm of two prime numbers a and b is _________ |
| A. | a⁄b |
| B. | ab |
| C. | a + b |
| D. | 1 |
| Answer» C. a + b | |
| 47. |
A number greater than 32 would require a minimum of how may bits in binary representation? |
| A. | 5 |
| B. | 6 |
| C. | 4 |
| D. | 10 |
| Answer» C. 4 | |
| 48. |
Electronic Code Book process is used in ________ |
| A. | caesar cipher |
| B. | antisymmetric cipher |
| C. | block cipher |
| D. | stream cipher |
| Answer» D. stream cipher | |
| 49. |
In binary signed representation if most significant bit is one then that number is positive. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 50. |
For some number a, b and c, aᶜ x bᶜ is equal to _________ |
| A. | (ab)ᶜ |
| B. | (ac)ᵇ |
| C. | (cb)ᵃ |
| D. | None of the mentioned |
| Answer» B. (ac)ᵇ | |