1. A computer virus is a
a) Hardware
b) Software
c) Bacteria
d) Freeware
2. Which of the following is NOT a goal of network security?
a) Confidentiality
b) Integrity
c) Availability
d) Denial of Service (DoS)
3. In computing, _____________ is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules.
a) Spyware
b) Cookie
c) Spam
d) Firewall
4. _____________ ensures that the message is real, accurate and safeguards from unauthorized user modification during the transmission.
a) Authentication
b) Non-repudiation
c) Integrity
d) None of the above
5. What does DDoS stand for?
a) Data Denial-of-Service
b) Distributed Denial-of Service
c) Distributed Data of Server
d) Distribution of Data Service
6. Conventional cryptography also known as ____________ encryption.
a) Asymmetric-key
b) Logical-key
c) Symmetric-key
d) None of these
7. In cryptography, the order of letters in a message is rearranged by ______________
a) Transpositional ciphers
b) Quadratic ciphers
c) Substitution ciphers
d) Both (a) and (c)
8. In symmetric-key cryptography, the key locks and unlocks the box is
a) Shared
b) Same
c) Private
d) Public
9. The plaintext encrypts to different cipher text with different keys
a) True
b) False
10. Which of the following is an ingredient of public key encryption?
(i) Plaintext (ii) Public and Private Key (iii) Decryption Algorithm
a) ii and iii
b) i, ii and iii
c) i and iii
d) i and ii
11. The information that gets transformed in encryption is
a) Plain text
b) Decrypted text
c) Parallel text
d) Encrypted text
12. A substitution cipher replaces symbols in a
a) block of packets
b) block of messages
c) block of characters
d) block of codes
13. Which of the following is an example of a symmetric key cipher?
a) RSA
b) Diffie-Hellimen
c) DES
d) Digital Signature Algorithm
14. Which one is DES?
a) Block cipher
b) Bit cipher
c) Stream cipher
d) None of the above
15. An asymmetric-key cipher uses
a) 1 Key
b) 2 Key
c) 3 Key
d) 4 Key
16. Cryptography term is used to transforming messages to make them secure and to prevent from
a) Change
b) Defend
c) Idle
d) Attacks
17. Shift cipher is also referred to as the
a) Caesar cipher
b) cipher text
c) Shift cipher
d) None of the above
18. Which one is the Heart of Data Encryption Standard (DES)?
a) DES function
b) Encryption
c) Rounds
d) Cipher
19. DES stands for ______________
a) Data Encryption Slots
b) Data Encryption Subscription
c) Data Encryption Standard
d) Data Encryption Solutions
20. 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
21. In cryptography, the original message before being transformed, is
a) Simple Text
b) Cipher Text
c) Empty Text
d) plain text
22. 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
23. 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
24. Which of these is NOT involved in the CIA Triad ?
a) Confidentiality
b) Availability
c) Integrity
d) Authenticity
25. 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
26. 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
27. 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
28. The encryption technique that uses one message to hide another message is called _____ .
a) MDA
b) Hashing
c) Steganography
d) None of the above
29. ________ is the term used in computer security to protect your data from getting disclosed.
a) Integrity
b) Authentication
c) Confidentiality
d) Availability
30. ___________ 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
31. 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
32. 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
33. 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
34. What is data encryption standard (DES)?
a) block cipher
b) stream cipher
c) bit cipher
d) byte cipher
35. In cryptography, the order of the letters in a message is rearranged by
a) transposition ciphers
b) substitution ciphers
c) both
d) quadratic ciphers
36. 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
37. 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
38. A straight permutation cipher or a straight p-box has the same number of input as
a) Cipher
b) Frames
c) Outputs
d) Bits
39. A person who enjoys learning details about computers and how to enhance their capabilities.
a) Cracker
b) Hacker
c) app controller
d) site controller
40. A process of making the encrypted text readable again.
a) Decryption
b) Encryption
c) network security
d) information hiding
41. The process of transforming plain text into unreadable text.
a) Decryption
b) Encryption
c) network security
d) information hiding
42. A transposition cipher reorders (permutes) symbols in a
a) block of packets
b) block of slots
c) block of signals
d) block of symbols
43. Cryptography, a word with Greek origins, means
a) corrupting data
b) secret writing
c) open writing
d) closed writing
44. In public key cryptosystem __keys are used for encryption and decryption.
a) Same
b) Different
c) encryption keys
d) none of the mentioned
45. Suppose that everyone in a group on N people wants to communicate secretly with the (N-1) others using symmetric key cryptographic system. The communication between any two people should not be decodable by the others in the group. The number of keys required in the system as a whole to satisfy the confidentiality requirement is
a. 2N
b. N(N-1)
c. N(N-1)/2
d. (N-1)2
46. Use Caesar’s Cipher (shift by 3) to decipher “KHOOR ZRUOG”.
a. HELLO WORLD
b. GOODBYE MOON
c. SECRET CODES
d. HIDDEN PLACE
47. Use Caesar’s Cipher to decipher “HQFUBSWHG WHAW”
a. ABANDONED LOCK
b. ENCRYPTED TEXT
c. ABANDONED TEXT
d. ENCRYPTED LOCK
48. 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)
49. For RSA to work, the value of P must be less than the value of
a) P
b) Q
c) N
d) F
50. 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
51. 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
52. 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
53. 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
54. The DES algorithm has a key length of
a) 128 bits
b) 32 bits
c) 64 bits
d) 16 bits
55. The number of unique substitution boxes in DES after the 48 bit XOR operation are
a) 8
b) 4
c) 6
d) 12
56. The Initial Permutation table/matrix is of size
a) 16×8
b) 4×8
c) 12×8
d) 8×8
57. DES follows
a) hash algorithm
b) caesars cipher
c) feistel cipher structure
d) sp networks
58. The DES Algorithm Cipher System consists of ____rounds (iterations) each with a round key.
a) 9
b) 12
c) 18
d) 16
59. 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
60. The 4×4 byte matrices in the AES algorithm are called
a) States
b) Words
c) Transitions
d) Permutations
61. 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
62. 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
63. Chosen cipher text attack is based on
a) Cryptanalysis
b) Cryptography
c) Encryption
d) Decryption
64. Rail Fence Technique is an example of
a) Substitution Cipher
b) Transposition Cipher
c) product cipher
d) ceaser cipher
65. Public key encryption is advantageous over Symmetric key Cryptography because of
a) Speed
b) Space
c) key exchange
d) key length
66. The sub key length at each round of DES is
a) 32
b) 56
c) 48
d) 64
67. Which algorithm can ensure data integrity?
a) RSA
b) AES
c) MD5
d) PKI
68. SHA-1 produces a hash value of
a. 256 bits
b. 160 bits
c. 180 bits
d. 128 bits
69. SHA-256 produces a hash value of
a. 160 bits
b. 128 bits
c. 256 bits
d. 512 bits
70. Which of the following statement (s) is/are correct regarding digital certificates?
i. A digital certificate binds a public key to the identity of the certificate.
ii. Digital certificates are always issued by government authorities only.
iii. Digital certificates can include expiration dates and revocation information.
a. Only i
b. ii and iii
c. Only iii
d. i and iii
71. Which of the following statement (s) is/are correct regarding digital certificates?
i. A digital certificate does not include the name of the CA who issues it.
ii. Digital certificates are based on public key cryptography.
iii. These certificates are available only in the strength i.e., 128-bit encryption.
a. Only iii
b. (i) and (iii)
c. Only (ii)
d. (i) and (ii)
72. A sender S sends a message m to the receiver R, which is digitally signed by S with its private key. In this scenario, one or more of the following security violations can take place.
i. S can launch a birthday attack to replace m with a fraudulent message.
ii. A third-party attacker can launch a birthday attack to replace m with a fraudulent message.
iii. R can launch a birthday attack to replace m with a fraudulent message.
Which of the following are possible security violations?
a. (i) and (ii) only
b. (i) only
c. (ii) only
d. (ii) and (iii) only
73. A sender S sends an encrypted message m to receiver R using asymmetric encryption, where S encrypts the message with R’s public key. In this scenario, one or more of the following security violations can take place.
i. S can launch a man-in-the-middle attack to alter the message.
ii. A third-party attacker can intercept and decrypt the message using R’s private key.
iii. R can launch a replay attack to resend the message as if it came from S.
Which of the following are possible security violations?
a. (i) and (ii) only
b. (ii) only
c. (iii) only
d. (i) and (iii) only
73. A digital signature is required:
a. for non-repudiation of communication by a sender
b. for all e-mail sending
c. for all DHCP server
d. for FTP transaction