1.
Introduction
2.
Problems
3.
4.
Conclusion
Last Updated: Mar 27, 2024

# Network Security

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## Introduction

As the name implies, network security is the method or attempts to protect the network via which we transfer data and use it daily.

Network security is a collection of rules, conditions, and configurations meant to secure the network's integrity.

It also uses software and hardware solutions to safeguard the network's secrecy and regulate network accessibility.

The most important feature and approach for any business to defend themselves from cyberattacks is network security.

## Problems

Now, we will see gate questions on Network Security with their solutions and explanations.

1. Take a look at the following statements:

i. An injective function is a hash function (which is commonly used to compute digital signatures).
ii. A permutation is performed on the elements of the input alphabet by an encryption technology like DES.

Which of the alternatives applies to the above two statements?

a. Both are false
b. i statement is correct, but ii statement is incorrect.
c. ii is correct, whereas i is incorrect.
d. Both are correct.

Ans: c

Explanation:
1) A hash function H(X) is a mapping from a bigger set to a predetermined output set in general.
2) It conducts P-Box permutation in the DES encryption technique.
Statement 1 is incorrect, but Statement 2 is correct.

2. A public-key encryption system

a. Anyone may decipher messages using a public key encryption method.
b. Only enables the data to be decoded by the correct sender.
c. Only allows the data to be decoded by the correct receiver.
d. does not encrypt the data before sending it.

Ans: c

Explanation: Public-key encryption is a cryptographic approach that uses a public key that everyone knows about and a private or secret key that only the message's receiver knows about. The recipient can decode the message using his private key and the sender's public key. As a result, the correct response is (C).

3. On the internet, the standard for certificates is?

a. X.25
b. X.409
c. X.301
d. X.509

Ans: d

Explanation: X.509 is a cryptography standard that specifies the format for public-key certificates. Many Internet protocols employ X.509 certificates, notably TLS/SSL, the foundation for HTTPS, the secure online surfing standard. Option (D) is the correct answer.

4. Assume that everyone in a group of N persons wishes to use an asymmetric key cryptography system to communicate privately with the Nâ€“1 others. The conversation between two people should be incomprehensible to the rest of the group. The total number of keys necessary to meet the secrecy criterion in the system is

a. N(N-1)
b. N(N-1)^2
c. (N-1)^2
d. N(N-1)/2

Ans: d

Explanation: Both parties have access to the key in Symmetric Key Cryptography. Each user must connect with N-1 other users using various keys, such as 1+2+3... N-2+N-1 N(N-1)/2 is the number of edges required in a complete graph with N vertices. Therefore, the correct answer is D.

5. The minimum positive integer p such that 3^p modulo 17 = 1 is

a. 5
b. 8
c. 12
d. 16

Ans: a

Explanation: Use Fermat's Little Theorem or the value of p to find the solution. Option (D) is the correct answer.

6. The total number of keys necessary for a group of n persons to communicate using the secret key and public key crypto-systems, respectively, is:

a. n(n-1) and 2n
b.2n and ((n(n - 1))/2)
c.((n(n - 1))/2) and 2n
d.((n(n - 1))/2) and n

Ans: c

Explanation: If there are two people, the total number of different communication keys is one. Similarly, we'll need two different keys for three people. We'll need n-1 keys, just like we'll need ways for n users. As a result, the total number of keys will be 1+2+3+... (n (n-1)/2) = n-1. In a public-key encryption technique, each person will have two keys. There are two keys: one public and one secret. As a result, we'll need 2* n keys to communicate with n people. As a result, the correct answers are ((n(n â€“ 1)/2) and 2n.

7. In an RSA cryptosystem, participant A generates his public and private keys using two prime numbers, p=13 and q=11. If A's public key is 37, then A's private key is?

a.13
b. 35
c. 11
d. 17

Ans: d

Explanation: Private Key = (n, d) Public Key = (n, e)
n = pq = 143 z = (p-1)(q-1) = 120  Given e = 37
Using ed mod z = 1 Candidates for 1 mod z = 121 241 361 481 601 721 841 961 1081 1201 1321 1441 1561 1681 1801 1921 2041 2161 2281 2401 2521 2641 2761 2881 3001 3121 3241 3361 3481 3601
The smallest number, which is a multiple of 37, is 481, and 481/37 = 13, So the private key is 13. Therefore Option (A) is correct.

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

i. SHA-256
ii. AES
iii. DES
iv. MD5

a. i and iv only
b.i and ii only
c.iii and iv only
d.i and iii only

Ans: a

9. The Feistel structure is used in which of the following encryption algorithms?

b.RC4
c.Data Encryption Standard
d.RSA public key cryptographic algorithm

Ans: c

Explanation: Feistel Cipher is a design concept from which many distinct block ciphers are developed, rather than a single block cipher scheme. A Feistel Cipher, such as DES, is just one example. The same technique is used for encryption and decryption in a cryptographic system based on the Feistel cipher structure. Option (C) is the correct answer.

10. MD5 is a popular hash algorithm for generating hash values of?

a. 128 bits
b. 64 bits
c. 512 bits
d. 1024 bits

Ans: b

We will close the article now with faqs since you got some idea of the gate questions of Network Security.

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1. What is network security?
The practice of taking precautions to safeguard the underlying networking infrastructure against illegal access, abuse, malfunction, alteration, destruction, or incorrect disclosure is known as network security.
2. Why is network security important?
Most things in the world are becoming digitalized over time. With that comes the need for data and personal information, which is the most critical and classified data in today's society, and it must be secured from misuse. As a result, network security is essential to protect the data.
3. How do I set up a personal firewall on my computer?
The firewall may be enabled in the system's control panel by selecting Windows Firewall under the system and security option.
4. What are the vulnerabilities of computer systems that should be protected?
The vulnerabilities of computer systems that should be protected are Locations, Data, Devices, Users, and Applications.
5. What are the three levels of network security?
Hardware, software, and cloud services are the three levels of network security.