Multiple Choice Questions on CNS & IS (Part 2)

MCQs on CNS & IS

1.  The _______________ attack is related to confidentiality.

• fabrication
• interception
• interruption
• modification

2.  If the recipient of the message has to be satisfied with the identity of the sender, the principle of ________________ comes into picture.

• authentication
• confidentiality
• integrity
• access control

3.  The ______________ attack is related to availability. 

• fabrication
• interception
• interruption
• modification

4.  If we want to ensure the principle of __________________, the content of a message must not be modified while in transit.

• authentication
• access control
• confidentiality
• integrity

5.  Interruption attacks are also called as ______________ attack. 

• alteration
• Denial of Service (DoS)
• masquerade
• replay attacks

6.  An example of poly-alphabetic substitution is

• Ceasar cipher
• Rail Fence transposition cipher
• Columnar transposition cipher
• Vigenere cipher

Explanation:

• Using more than one alphabet and switching between them systematically to encrypt data is called a polyalphabetic substitution cipher. 
• The Vigenere cipher is a method of encrypting alphabetic text by using a series of interwoven Caesar ciphers based on the letters of a keyword. 
• It is a form of polyalphabetic substitution. 

7.  A Substitution Box provides ____________________. 

• diffusion only
• confusion only
• both diffusion and confusion
• neither diffusion nor confusion

8.  The number of rounds in 56-bit DES and 128-bit DES are respectively: 

• 12 and 12
• 12 and 16
• 16 and 16
• 16 and 20

9.  A public key encryption system

• allows anyone to decode the transmissions
• allows only the correct sender to decode the data
• allows only the correct receiver to decode the data
• doesn't decode the data before transmitting it

10.  A MAC provides ___________________________.

• message integrity
• message authentication
• message confidentiality
• message integrity and authentication

11. A MAC may be implemented using DES in ________ mode. 

• Electronic Code Book (ECB)
• Cipher Block Chaining (CBC)
• Cipher FeedBack (CFB)
• Counter (CTR)

12.  The principal advantage of Public Key cryptography over Secret Key cryptography is ______________________.

• simplified key management
• lower chip area
• improved speed
• higher security

13.  Which of the following is/are synonymous with "hash of a message"?

• Digital signature over a message
• Message Digest
• Message Authentication Code (MAC)
• Message Fingerprint

14.  The digital signature provides which of the following service(s)?

• Message confidentiality
• Message integrity
• Message authentication
• Non-repudiation

15.  To verify a digital signature, which of the following components are required?

• The signer's private key
• The signer's public key
• The hash algorithm used
• The verifier's public key