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# CS6701 Question Bank Cryptography and Network Security

CS6701 Question Bank Cryptography and Network Security Regulation 2013 Anna University free download. Cryptography and Network Security CS6701 Question Bank pdf free download.

## Sample CS6701 Question Bank Cryptography and Network Security:

1. Specify the four categories of security threads? ._Interruption
._Interception ._Modification ._Fabrication

2. Explain active and passive attack with example? Passive attack:
Monitoring the message during transmission. Eg: Interception
Active attack:
It involves the modification of data stream or creation of false data stream. E.g.: Fabrication,
Modification, and Interruption CS6701 Question Bank Cryptography and Network Security

3. Define integrity and nonrepudiation? Integrity:
Service that ensures that only authorized person able to modify the message.
Nonrepudiation:
This service helps to prove that the person who denies the transaction is true or false. CS6701 Question Bank Cryptography and Network Security

4. Differentiate symmetric and asymmetric encryption?

Symmetric Asymmetric
It is a form of cryptosystem in which encryption and decryption performed using the same key.
It is a form of cryptosystem in which encryption and decryption Performed using two keys.
Eg: DES, AES Eg: RSA, ECC CS6701 Question Bank Cryptography and Network Security

5. Define cryptanalysis?
It is a process of attempting to discover the key or plaintext or both.

6. Compare stream cipher with block cipher with example. Stream cipher:
Processes the input stream continuously and producing one element at a time. Example: caeser
cipher.
Block cipher:
Processes the input one block of elements at a time producing an output block for each input
block.
Example: DES. CS6701 Question Bank Cryptography and Network Security

7. Define security mechanism
It is process that is designed to detect prevent, recover from a security attack. Example:
Encryption algorithm, Digital signature, Authentication protocols.

8. Differentiate unconditionally secured and computationally secured
An Encryption algorithm is unconditionally secured means, the condition is if the cipher text
generated by the encryption scheme doesn’t contain enough information to determine
corresponding plaintext. CS6701 Question Bank Cryptography and Network Security
Encryption is computationally secured means,
1. The cost of breaking the cipher exceed the value of enough information.

2. Time required to break the cipher exceed the useful lifetime of information.

 Subject Name Cryptography and Network Security Subject code CS6701 Regulation 2013