Revision to Data security:

MCQ:
1) ……………….means that changes need to be done only by
authorized entities and through authorized mechanisms.
a) Confidentiality.
b) Integrity.
c) Availability
d) Authentication
2) The organizational resource that is being protected.
a) Access
b) Asset
c) Exposure
d) Attack
3) Security mechanisms, policies, or procedures that can successfully counter
attacks.

a) Control
b) Safeguard
c) Countermeasure
d) All of the above
4) ………………..exists when a vulnerability known to an attacker is present.
a) Exposure
b) Loss
c) Risk
d) Access
5) An intentional or unintentional act that can cause damage to or otherwise
compromise information and/or the systems that support it.
 a) Access

b) Asset
c) Exposure

d) Attack
6) ……………….assaults may be performed using the stolen passwords and logins
a) Modification
b) Repudiation
c) Masquerade
d) Replay
7) ………………. is an attack on the integrity of the original data.
a) Modification
b) Repudiation
c) Masquerade
d) Replay
8) ………………. It prevents the normal use of communication facilities
a) Repudiation
b) Denial of Service
c) Masquerade
d) Replay 9)
The original message

a) Plaintext
b) Ciphertext
c) Enciphering
d) Deciphering
10) Techniques used for deciphering a message without any knowledge of the
enciphering details

a) Enciphering
b) Deciphering
 c) Cryptanalysis
d) Cryptography
11) Areas of cryptography and cryptanalysis together
a) Deciphering
b) Enciphering
c) Cryptographic system or cipher
d) Cryptology
12) Schemes used for encryption
a) Deciphering
b) Enciphering
c) Cryptographic system or cipher
d) Cryptology
13) …………………..is the science of using mathematics to encrypt and decrypt data
a) Cryptography

b) Cryptographic system or cipher

c) Cryptanalysis
d) Cryptology
14) …………………..It Cryptanalysis involves the study of cryptographic
mechanism with the intention to break them.
a) Cryptography
b) Cryptographic system or cipher

c) Cryptanalysis
d) Cryptology
15) ……………………is the process by which a readable message is converted to an
unreadable.
 a) Encryption
b) Decryption
c) Cryptanalysis
d) Cryptology
16) The classification to cryptography system according to the type of
operations used for transforming plaintext to ciphertext.

a) Substitution & Transposition

b) Symmetric & Asymmetric
c) Block cipher & Stream cipher
d) There is no answer
17) The classification to cryptography system according to the way in which the
plaintext is processed.

a) Substitution & Transposition

b) Symmetric & Asymmetric
c) Block cipher & Stream cipher
d) There is no answer
18) The public key is…………..
a) Symmetric

b) Asymmetric

c) Block

d) Stream

19) ………………… is designed to protect data from disclosure attack and

also protection against traffic analysis.
a) Data confidentiality
b) Data integrity
c) Nonrepudiation
d) Access Control
20) ………………. is designed to protect data from modification, insertion,
deletion, and replaying by an adversary
a) Nonrepudiation
b) Data confidentiality
c) Data integrity
d) Access Control
21) In ................The sender of data can later prove that data were
delivered to the intended recipient.
a)
Nonrepudiation
b)
Access Control
c)
Data integrity
d)
Data confidentiality
22) ………………..provides protection against unauthorized access to data.
a) Nonrepudiation
b) Access Control
c) Data integrity
d) Data confidentiality
23) The classification to cryptography system according to the
number of keys used
a) Substitution & Transposition
b) Symmetric & Asymmetric
c) Block cipher & Stream cipher
d) There is no answer
24) Plain text with the key does ..............and is given.........
a) Encryption and Plain text
b) Encryption and Cipher text
c) Decryption and Plain text
d) Decryption and Cipher text
25) Cipher text with the key does..............and is given.........
a) Encryption and Plain text
b) Encryption and Cipher text
c) Decryption and Plain text
d) Decryption and Cipher text
26) What mechanism appends to the data a short check value?
a) Data Integrity
b) Notarization
c) Traffic Padding
d) Authentication Exchange
27) What is a means by which the sender can electronically sign
the data and the receiver can electronically verify the signature?
 a) Notarization
b) Traffic Padding
c) Authentication Exchange
d) Digital Signature
28) What is means inserting some bogus data into the data traffic
to thwart the adversary’s attempt?
a) Notarization
b) Traffic Padding
c) Authentication Exchange
d) Digital Signature
29) What is mean selecting a third trusted party to control the
communication between two entities?
a) Notarization
b) Traffic Padding
c) Authentication Exchange
d) Digital Signature
30) In............are shifting the letters of a message by an agreed
number.
a) Caesar Cipher
b) Steganography
c) Vigenere Cipher
d) Playfair Cipher
31) In.................people want to make sure that no unauthorized
person obtains proof that the information exists.
a) Caesar Cipher
b) Steganography
c) Vigenere Cipher
d) Playfair Cipher
32) What is the technique that moves letters in a message in
number of variable places instead of moving them in the same
number of places?
a) Caesar Cipher
b) Steganography
c) Vigenere Cipher
d) Playfair Cipher
33) Persons must share a common key prior to exchange of
information. In..................
a) Symmetric Key
b) Asymmetric Key
c) Substitution
d) Stream cipher
34) In a group of n people, to enable two-way communication
between any two people, the number of keys required for the group is
in stat use symmetric key :
a) N÷ (n – 1)+2
b) n × (n + 3)/2
c) n × (n – 1)/2
d) n × (n + 1)/2
35) In which system requires the public key to be placed in a public
repository and the private key in a well-guarded archive?
a) Symmetric Key
b) Fixed key
c) Preset key
d) Asymmetric Key
36) When using ..............the processing power of the computer
system required to run algorithm is less.
a) Symmetric Key
b) Asymmetric Key
c) Substitution
d) Stream cipher
37) In this system, the user needs a pair of different keys, the
private key and the public key.
a) Symmetric Key
b) Fixed key
c) Asymmetric Key
d) Preset key
38) There must be a robust key exchange mechanism between
communicating parties. In...............
a) Symmetric Key
b) Asymmetric Key
c) Substitution
d) Stream cipher
39) When using................It is recommended to change the keys
regularly to prevent any attack on the system.
a) Symmetric Key
b) Asymmetric Key
c) Substitution
d) Stream cipher
40) When using ..............the processing power of the computer
system required to run algorithm is higher.
a) Symmetric Key
b) Asymmetric Key
c) Substitution
 d) Stream cipher
41) In which this method, the attacker has access to a set of cipher
text?
a) Cipher text Only Attacks (COA)
b) Known Plaintext Attack (KPA)
c) Dictionary Attack
d) Brute Force Attack (BFA)
42) In which this method, the attacker knows the plaintext for
some parts of the cipher text?
a) Cipher text Only Attacks (COA)
b) Known Plaintext Attack (KPA)
c) Dictionary Attack
d) Brute Force Attack (BFA)
43) Is the simplest method of attack, the attacker builds a file A
dictionary of cipher texts and corresponding plaintexts.
a) Cipher text Only Attacks (COA)
b) Known Plaintext Attack (KPA)
c) Dictionary Attack
d) Brute Force Attack (BFA)
44) In which method, the attacker attempts to identify the key by
trying all possible keys?
a) Cipher text Only Attacks (COA)
b) Known Plaintext Attack (KPA)
c) Brute Force Attack (BFA)
d) Dictionary Attack
45) What attack is used against the cryptographic hash
function?
a) Man in Middle Attack (MIM)
b) Brute Force Attack (BFA)
c) Birthday Attack
d) Dictionary Attack
46) If an attacker is able to find two different entries that give
the same hash value, then this is.............
a) Man in Middle Attack (MIM)
b) Brute Force Attack (BFA)
c) Birthday Attack
d) Dictionary Attack
47) Which of these is the target of mostly public key encryption
systems where keys are exchanged before a connection is made?
a) Man in Middle Attack (MIM)
b) Brute Force Attack (BFA)
c) Birthday Attack
d) Dictionary Attack
48) Substitution Cipher may be inside it:
a) Substitution & Transposition
b) Symmetric & Asymmetric
c) Block cipher & Stream cipher
d) Monoalphabetic & Polyalphabetic
49) Relationship one to one is
a) Polyalphabetic
b) Monoalphabetic
c) Substitution
d) Transposition
50) relationship one to many is
a) Polyalphabetic
b) Monoalphabetic
c) Substitution
d) Transposition
51) Each letter or group of letters is replaced by another letter or group
of letters
a) Polyalphabetic
b) Monoalphabetic
c) Substitution
d) Transposition
52) Rearranges the position of the plain text’s characters. The position of
the character is changed but character’s identity is not changed.
a) Polyalphabetic
b) Monoalphabetic
c) Substitution
d) Transposition
53) In this example, what is the cipher text? “Computer science”, with
key = left shift by 8 characters. Use Caesar Cipher?
a) UFEHMLWJKUAWFUF
b) AGEHMLDJKUAWFUW
c) UKEHMFWJKUAWFUW
d) UGEHMLWJKUAWFUW
54) In this example, what is the cipher text? “Hello”, with key = 5
characters. Use Mono Alphabetic Substitution Cipher?
a) MJQQT
b) LIPPS
c) NKRRU
d) JGNNQ

55) In…………….cipher each occurrence of a character may have different

substitution.
a) Polyalphabetic
 b) Monoalphabetic
c) Substitution
d) Transposition
56) In this example, what is the Encryption? “ABCDEFGH”, with key = {0,
5, 8} characters. Use Vigener cipher?
a) AGKD
b) JNGM
c) AGKDJNGM
d) JNGM AGKD

57) In this example, what is the decryption? “K E N T U T G B O X”, with

key = BEST characters. Use Vigener cipher?
a) T B E S T P O I N T
b) J A V A T P O I N T
c) J A V A T P B E S T
d) P O I N T J A V A T
58) It is considered a Vigenere encryption
a) Substitution and Symmetric, Block cipher
b) Transposition and Asymmetric, Stream cipher
c) Transposition and Asymmetric, Block cipher
d) Substitution and Symmetric, Stream cipher
59) In this example, “hide money”, with key = “tutorials” characters. Use
Playfair Cipher? What is the Encryption the “HI DE MO NE YZ”
a) HI DE MO NE YZ
b) QC FE NU MF ZV
c) ZV QC EF NU MF
d) QC EF NU MF ZV

T U O R I
A L S B C
D E F G H
K M N P Q
V W X Y Z
Key Table1
60) Based on the previous Key Table1. What is the Encryption the
“VZ” Use the Rules of Playfair Cipher?
a) KQ
b) WY
c) WV
d) WZ
61) Based on the previous Key Table1. What is the Decryption the
“UD” Use the Rules of Playfair Cipher?
a) TE
b) UD
c) OE
d) SM
62) In this example, what is the encryption? Plain text = “golden statue is
in eleventh cave”, with key = 5. Use Keyed transposition cipher?
a) “Etivcgnuneaoseenvltiltedaseh”
b) “goldenstatueisineleventhcave”
c) “Gnuneaoseenvltiltedasehetivc”
d) “Gnuneaoseenvltiltedaseh”
63) There are 42 characters in the cipher text, and the keyword is 8
letters, so how many rows are needed to decrypt.
a) 5
b) 7
c) 3
d) 6
64) For DES, data are encrypted in 64-bit blocks using a…………bit key
a) 48
b) 32
c) 56
d) 64
65) Example: Find the output of the initial permutation box when the
input is given in hexadecimal as: 0x0002 0000 0000 0001
a) 0x0000 0080 0000 0002
b) 0x0005 0000 0000 0002
c) 0x0000 0000 0000 0002
d) 0x0000 0010 0000 0002
66) In the example, get key 56-bit: Let K be
the hexadecimal key K = 133457799BBCDFF1.
a) K+ = 1111000 0110011 0010101 0101111 0101010 1011001 1001111
0001111
b) K+ = 00010011 00110100 01010111 01111001 10011011 10111100
11011111
c) K+ = 00110100 01010111 01111001 10011011 10111100 11011111
11110001
d) K+ = 00010011 00110100 01010111 10011011 10111100 11011111
11110001
67) From the previous key find C3 ,D3
a) C3 = 1111000011001100101010101111
D3 = 0101010101100110011110001111
b) C3 = 1110000110011001010101011111
D3 = 1010101011001100111100011110
 c) C3 = 0011001100101010101111111100
D3 = 0101100110011110001111010101
d) C3 = 0000110011001010101011111111
D3 = 0101011001100111100011110101
68) Example: If the output of permutation operation is: 1 0 1 0 1 1
Becomes as input to S-box 1
a) 0011
b) 1100
c) 0100
d) 0010