FFY Center for Learning (CSE): Multiple Choice Questions on CNS & IS (Part 1)

MCQs on CNS & IS

1. Which of the following term indicates that the data is not modified by unauthorised users?

2. Authentication is used for which of the following?

3. Which device connects multiple networks?

4. Information Security is for protecting which of the following?

5. Reconnaissance means ________________.

6. Which security service ensures that data is protected from unauthorised disclosure.

7. Which of the following encryption algorithms is based on the Fiestal structure?

Explanation:

Feistel Cipher is not a specific scheme of block cipher, it is a design model from which many different block ciphers are derived.
DES is just one example of a Feistel Cipher.
A cryptographic system based on Feistel cipher structure uses the same algorithm for both encryption and decryption.

8. Which one of the following algorithm is not used in asymmetric key cryptography?

Explanation:

RSA algorithm and Diffie-Hellman algorithm are popular asymmetric key cryptographic algorithms.
RSA is used for encryption and decryption, while Diffie-Hellman is used for key exchange.
Electronic Code Book (ECB) algorithm is a symmetric key cryptographic algorithm in which the same key is used for both encryption and decryption.

9. Which one of the following is true for asymmetric-key cryptography?

Private key is kept by the receiver and the public key is announced to the public.
Public key is kept by the receiver and the private key is announced to the public.
Both private key and the public key are kept by the receiver.
Both private key and the public key are announced to the public.

10. A sender is employing public key cryptography to send a secret message to a receiver. Which one of the following statements is TRUE?

11. Hashed message is signed by a sender using his ___________________.

Explanation:

After the generation of hash value (also called message digest) that needs to be transmitted over a network, it is signed (encrypted) using the private key of the sender which is known as digital signature.
The message is transmitted along with the digital signature which ensures authentication and non-repudiation.

12. Anarkali digitally signs a message and sends it to Salim. Verification of the signature by Salim requires ____________________.

13. Which of the following are used to generate a message digest by the network security protocols?

Explanation: SHA 1 and MD5 are used to generate a message digest by the network security protocols.

RSA – It is an algorithm used to encrypt and decrypt messages.
SHA 1 – Secure Hash Algorithm 1, or SHA 1 is a cryptographic hash function. It produces a 160 bit (20 byte) hash value (message digest).
DES – Data Encryption Standard, or DES is a symmetric key algorithm for encryption of electronic data.
MD5 – Message Digest 5, or MD5 is a widely used cryptographic hash function that produces a 128 bit hash value (message digest).

14. MD5 is a widely used hash function for producing hash value of ____________.

15. Pretty Good Privacy (PGP) is used in ______________.

Explanation:

PGP is a an encryption phenomena that provide cryptographic privacy and authentication for data communication over e-mails.
It generates a public key to encrypt a message at sender's end and private key to decrypt a message at receiver's end allowing us to send files and messages securely over internet.
OpenPGP is an email encryption standard.
It uses Digital Signatures to provide authentication and integrity checking basically to check if the message is actually sent by the person or entity claimed to be the sender.