DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

Document Sample
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING Powered By Docstoc
					        DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING
                            Two Mark Questions & Answers
      CS431-NETWORK PROTOCOLS MANAGEMENT AND SECURITY
11.What do you mean by Fabrication?
        When an unauthorized party inserts counterfeit objects in to the system then it is
called as fabrication this is an attack on authenticity.

12.What do you mean by Passive attacks?
       Passive attacks are in the nature of eavesdropping on or monitoring of
transmissions.

13.What do you mean by Active attacks?
        Active attacks are involve some modification of the data stream or the creation of
a false stream.

14.What are the different types of passive attacks and passive attacks?
      Passive attacks:
               Release of message content.
               Traffic Analysis.
      Active attacks:
                            Replay
                            Masquerade
                            Denial of service
                            Modification of message.

15.What do you mean by Replay?
      Making a passive capture of message and reusing it afterwards.

16.Define Cipher text and Plain text?
       The original intelligible message is referred as plaintext. Plain text is converted in
to apparently random nonsense and it is referred as Cipher text.

17.Define Encryption and Decryption?
       The process of converting the plain text in to cipher text is called as Encryption.
The process of recovering the plain text from the cipher text is called as Decryption.

18.What are the classical Encryption techniques?
      Substitution.
      Transposition.

19.Define Stream Cipher?
        Stream cipher is the one that encrypts a digital data stream one bit or one byte at a
time. (e.g) Vigenere cipher, Vernal cipher.

20. Define Block Cipher?
        A Block cipher is the one in which a block of plaintext is treated as a whole and
used to produce a cipher text block of equal length.

21.What do you mean by Avalanche effect?
        It is a desirable property of any encryption algorithm. It says that a small change
in either the plain text or the key should produce a significant change in the cipher text.


22.Give the formula used in RSA?
       C = Me Mod n                          M=Cd Mod n
       C- Cipher     M-Message       (e,n) – Public Key (d,n) – Private Key

23.What do you mean by Blinding in RSA?
       It is a method to prevent timing attack in RSA. By multiplying the cipher text
with a random number before performing exponentiation, we can prevent the attacker
from knowing what cipher text bits are being processed inside the computer and therefore
prevents bit by bit analysis essential to the timing attack.

24.What are the different methods for public key distribution?
      Public Announcement                    Publicly available Directory
      Public Key Authority                   Public key certificate.

25.What is MAC?
       The Message Authentication Code is the small fixed size block of data generated
using the secret key and the message and it is appended to the message to provide
authentication.

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:5
posted:9/29/2012
language:English
pages:2