NETWORK SECURITY AND CRYPTOGRAPHY BASICS SOLVED QUESTION AND ANSWERS
1. What is meant by network security.
Network security is the mechanism of protecting data flowing on a network from unauthorized access.
Some of the network security measures involves Data Encryption techniques and use of Passwords.
2. What is the difference between share level security and user level security.
Share level security: In share level security, access to a particular resource is based on password.
User level security: In user level security, access to a particular resource is based on username.
The security level of share level security is less than that of user level security because user level security is dependent on username.
Share level security<User level security
3. What is a security policy.
Security policy is a written document which states the rules and regulations by which all users of the network must abide by.
4. What is the difference between a hacker and cracker.
Hacker: A hacker is a person who writes programs in assembly language or system level languages.
Generally a hacker is supposed to be a honest person who works to break secret and security information of
unscrupulous persons. Example: Ethical Hacking
Cracker: A cracker is the one who breaks in to a computer system without authorization. His sole aim is to damage the systems of other people or group.
Example: Steal credit,debit card numbers,plant viruses, etc.
Note: Hacker-Good person
Cracker-Bad person.
5. What is spoofing.
Spoofing is the technique of creating fake responses to keep a session active and prevent timeouts.
It is also a network management technique to reduce traffic.
6. Expand NAT and its application.
NAT stands for Network Address Translation.
NAT hides the IP addresses of client stations in the network.
7. What is meant by cryptography.
Cryptography is the technique of converting plain text to cipher text and converting the cipher text to plain text.
8. What is public key cryptography.
Public key cryptography is also called as Asymmetric encryption.
It makes use of two keys-public key and private key
Public key is used to encrypt the message and Private key is used to decrypt the message.
Public key cryptography was invented by Whitefield diffie and martin hellman.
9. What is the difference between encryption and decryption.
Encryption means the conversion of original text(plain text) to cipher text(encrypted text)
Decryption means the conversion of cipher text(encrypted text) to original text(plain text).
10. What is the difference between symmetric encryption and asymmetric encryption. .
Symmetric encryption: It makes use of the same key both for encryption and decryption.
Asymmetric encryption: It makes use of two keys namely
Public key-Public key is used to convert the plain text to cipher text.(encryption)
Private key-Private key is used to convert cipher text to plain text.(decryption)
11. Which of the following is the size of Network bits and Host bits of Class A of IP address ?
Network bits 14, Host bits 16
12. Which of the following field of the TCP header tells how many bytes may be sent starting at the byte acknowledged ?
Window size
13. If user A wants to send an encrypted message to user B. The plain text of A is encrypted with the
Public Key of user B
14. A _____ can forward or block packets based on the information in the network layer and transport layer header.
Proxy firewall
15. Expand UDP and its use.
UDP stands for User Datagram Protocol.
UDP is a connectionless transport protocol.
Only 45 more days for UGC NET December 2013 exam.
1. What is meant by network security.
Network security is the mechanism of protecting data flowing on a network from unauthorized access.
Some of the network security measures involves Data Encryption techniques and use of Passwords.
2. What is the difference between share level security and user level security.
Share level security: In share level security, access to a particular resource is based on password.
User level security: In user level security, access to a particular resource is based on username.
The security level of share level security is less than that of user level security because user level security is dependent on username.
Share level security<User level security
3. What is a security policy.
Security policy is a written document which states the rules and regulations by which all users of the network must abide by.
4. What is the difference between a hacker and cracker.
Hacker: A hacker is a person who writes programs in assembly language or system level languages.
Generally a hacker is supposed to be a honest person who works to break secret and security information of
unscrupulous persons. Example: Ethical Hacking
Cracker: A cracker is the one who breaks in to a computer system without authorization. His sole aim is to damage the systems of other people or group.
Example: Steal credit,debit card numbers,plant viruses, etc.
Note: Hacker-Good person
Cracker-Bad person.
5. What is spoofing.
Spoofing is the technique of creating fake responses to keep a session active and prevent timeouts.
It is also a network management technique to reduce traffic.
6. Expand NAT and its application.
NAT stands for Network Address Translation.
NAT hides the IP addresses of client stations in the network.
7. What is meant by cryptography.
Cryptography is the technique of converting plain text to cipher text and converting the cipher text to plain text.
8. What is public key cryptography.
Public key cryptography is also called as Asymmetric encryption.
It makes use of two keys-public key and private key
Public key is used to encrypt the message and Private key is used to decrypt the message.
Public key cryptography was invented by Whitefield diffie and martin hellman.
9. What is the difference between encryption and decryption.
Encryption means the conversion of original text(plain text) to cipher text(encrypted text)
Decryption means the conversion of cipher text(encrypted text) to original text(plain text).
10. What is the difference between symmetric encryption and asymmetric encryption. .
Symmetric encryption: It makes use of the same key both for encryption and decryption.
Asymmetric encryption: It makes use of two keys namely
Public key-Public key is used to convert the plain text to cipher text.(encryption)
Private key-Private key is used to convert cipher text to plain text.(decryption)
11. Which of the following is the size of Network bits and Host bits of Class A of IP address ?
Network bits 14, Host bits 16
12. Which of the following field of the TCP header tells how many bytes may be sent starting at the byte acknowledged ?
Window size
13. If user A wants to send an encrypted message to user B. The plain text of A is encrypted with the
Public Key of user B
14. A _____ can forward or block packets based on the information in the network layer and transport layer header.
Proxy firewall
15. Expand UDP and its use.
UDP stands for User Datagram Protocol.
UDP is a connectionless transport protocol.
Only 45 more days for UGC NET December 2013 exam.
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