MCQ of Network Security and Cryptography

1. Which one is DES?

a)  Block cipher

b)  Bit cipher

c)   Stream cipher

d) None of the above

2. An asymmetric-key cipher uses

a)  1 Key

b)  2 Key

c)   3 Key

d) 4 Key

3. Cryptography term is used to transforming messages to make them secure and to prevent from

a)  Change

b)  Defend

c)   Idle

d) Attacks

4. Shift cipher is also referred to as the

a)  Caesar cipher

b)  cipher text

c)   Shift cipher

d) None of the above

5. Which one is the Heart of Data Encryption Standard (DES)?

a)  DES function

b)  Encryption

c)   Rounds

d) Cipher

6. DES stands for…………………

a)  Data Encryption Slots

b)  Data Encryption Subscription

c)   Data Encryption Standard

d) Data Encryption Solutions

7. What is cipher in Cryptography?

a)  Algorithm for performing encryption

b)   Algorithm for performing decryption

c)   Encrypted Messages

d) Both algorithm for performing encryption and Decryption and encrypted message

8. In cryptography, the original message before being transformed, is

 a)  Simple Text

b)  Cipher Text

c)   Empty Text

d)  plain text

9. Which of these is a technique that is used to verify a message’s integrity?

a)  Message Digest

b)  Protocol

c)   Decryption algorithm

d) Digital signature

10. Using the cipher algorithm, which of these types of text would be transformed?

 a)  Plain text

b)  Scalar text

c)   Complex text

d) Transformed text

11. Which of these is NOT involved in the CIA Triad ?

a)  Confidentiality

b)  Availability

c)   Integrity

d) Authenticity

12. ECB in the context of  digital cryptography stands for

a)  Electrical Circuit Board

b)  Electronic Code Book

c)   Electrical Code Book

d) Electronic Circuit Book

13. Which of the following statements describe a type of Phishing attack?

a)  Sending someone an email that contains a malicious link by disguising to appear like an email from someone the person knows.

b)  Creating a fake website that appears to be identical to the  real website and  trick users to enter  their login information

c)   Sending someone a text message that contains a malicious link that is disguised to look like a notification that the person has won a contest.

d) All of the above

14. Which one of the following techniques used by hackers to trick the users in order to disclose their username and passwords through fake websites? 

a)  Social Engineering

b)  Cookie stealing

c)   Phishing

d) Cyber stalking

15. The encryption technique that uses one message to hide another message is called _____ .

a)  MDA 

b)  Hashing

c)   Steganography

d) None of the above

16.  ________  is the term used in computer security to protect your data from getting disclosed.

 a)  Integrity 

b)  Authentication

c)   Confidentiality

d) Availability

17. ___________ is the term used in computer security to protect the data from being modified by the unauthorized user.

a)  Integrity

b)  Authentication

c)   Confidentiality

d) Availability

18. Which algorithm can ensure data integrity?

 a)  RSA

b)  AES

c)   MD5

d) PKI

19. What is the key space of an encryption algorithm ?

a)  the set of all possible values used to generate a key

b)  the set of procedures used to calculate asymmetric keys

c)   the set of hash functions used to generate a key

d) the mathematical equation that is used to create a key

20. Alice and Bob are using a digital signature to sign a document. What key should Alice use to sign the document so that Bob can make sure that the document came from Alice?

a)  private key from Bob

b)  private key from Alice

c)   public key from Bob

d) username and password from Alice

21. Which three security services are provided by digital signatures? (Choose three.)

a)  provides non-repudiation using HMAC functions

b)  guarantees data has not changed in transit

c)   provides data encryption

d) authenticates the source

e)  provides confidentiality of digitally signed data

f)    authenticates the destination

22. Cryptanalysis is used      

a)    to find some insecurity in a cryptographic scheme    

b)   to increase the speed

c)    to encrypt the data

d) to make new ciphers

23. What is data encryption standard (DES)?

a)  block cipher

b)  stream cipher

c)   bit cipher

d) byte cipher

24. In cryptography, the order of the letters in a message is rearranged by

a)  transposition ciphers

b)  substitution ciphers

c)   both

d) quadratic ciphers

25. In cryptography, what is cipher?

a)  algorithm for performing encryption and decryption

b)  encrypted message

c)   both algorithm for performing encryption and decryption and encrypted message

d) decrypted message

26. The man-in-the-middle attack can endanger the security of the diffie-hellman if two parties are not

a)  Authenticated

b)  Joined

c)   Submit

d) Separate

 27. A straight permutation cipher or a straight p-box has the same number of input as

a)  Cipher

b)  Frames

c)   Outputs

d) Bits

28. A person who enjoys learning details about computers and how to enhance their capabilities.

 a)  Cracker

b)  Hacker

c)   app controller

d) site controller

29. A process of making the encrypted text readable again.

a)  Decryption

b)  Encryption

c)   network security

d) information hiding

30. The process of transforming plain text into unreadable text.

a)  Decryption

b)  Encryption

c)   network security

d) information hiding

31. A transposition cipher reorders (permutes) symbols in a

a)  block of packets

b)  block of slots

c)   block of signals

d) block of symbols

32. Cryptography, a word with Greek origins, means

 a)  corrupting data

b)  secret writing

c)   open writing

d) closed writing

33. In public key cryptosystem __keys are used for encryption and decryption.

a)  Same

b)  Different

c)   encryption keys

d) none of the mentioned

34. In RSA, Ф(n) = in terms of p and q

a)  (p)/(q)

b)  (p)(q)

c)   (p-1)(q-1)

d) (p+1)(q+1)

35. For RSA to work, the value of P must be less than the value of 

a)  P

b)  Q

c)   N

d) F

36. In Asymmetric key Cryptography, although RSA can be used to encrypt and decrypt actual messages, it is very slow if the message is

 a)  Short

b)  Long

c)   Flat

d) Thin

37. Which of the following is not a type of symmetric-key cryptography technique?

a)  caesar cipher

b)  data encryption standard (des)

c)   diffie hellman cipher

d) playfair cipher

38. Computation of the discrete logarithm is the basis of the cryptographic system

a)  symmetric cryptography

b)  asymmetric cryptography

c)   diffie-hellman key exchange

d) secret key cryptography

39. Which of the following is a mode of operation for the Block ciphers in cryptography?

a)  electronic code book (ecb)

b)  cipher block chaining (cbc)

c)   counter (ctr) mode

d) all of the above

40. The DES algorithm has a key length of

a)  128 bits

b)  32 bits

c)   64 bits

d) 16 bits

41. The number of unique substitution boxes in DES after the 48 bit XOR operation are

a)  8

b)  4

c)   6

d)  12

42. The Initial Permutation table/matrix is of size 

a)  16×8

b)  4×8

c)   12×8

d) 8×8

43. DES follows  

a)  hash algorithm

b)  caesars cipher

c)   feistel cipher structure

d) sp networks

44. The DES Algorithm Cipher System consists of ____rounds (iterations) each with a round key. 

a)  9

b)  12

c)   18

d) 16

45. For the AES-128 algorithm there are __ similar rounds and __ round is different.

 a)  2 pair of 5 similar rounds ; every alternate

b)  9 ; the last

c)   8 ; the first and last

d) 10 ; no

46. The 4×4 byte matrices in the AES algorithm are called

a)  States

b)  Words

c)   Transitions

d) Permutations

47. 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

48. 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

49. Chosen cipher text attack is based on

 a)  Cryptanalysis

b)  Cryptography

c)   Encryption

d) Decryption

50. Rail Fence Technique is an example of

a)  Substitution Cipher

b)  Transposition Cipher

c)   product cipher

d) ceaser cipher

51. Public key encryption is advantageous over Symmetric key Cryptography because of 

a)  Speed

b)  Space

c)   key exchange

d) key length

52. The sub key length at each round of DES is 

a)  32

b)  56

c)   48

d) 64