Computer Network Security.

What is Computer Network Security ?

• Network security is any process or activity which is designed to protect the usability and integrity of network and data over it.
• Computer Security - It is generic name for the collection of tools designed to protect data and to thwart hackers.
• Network Security - It measures to protect data during their transmission over network.
• It includes both hardware and software technologies.
• It targets a variety of threats and It stops them from entering  on your network.
• Computer network security consists of measures taken by business or some organizations to monitor and prevent unauthorized access from the outside attackers.
• Impressive network security manages access to the network to provide security.

Note:- Different approaches to computer network security management have different requirements depending on the size of the computer network. For example, a home office requires basic network security while large businesses require high maintenance to prevent the network from malicious attacks.

Network Administrator

• Network Administrator controls access to the data and software on the network. 
• A network administrator assigns the user ID and password to the authorized person.
• Computer data often travels from one computer to another, leaving the safety of its protected physical surroundings. 
• Once the data is out of hand, people with bad intention could modify or forge your data, either for amusement or for their own benefit.
• Cryptography can reformat and transform our data, making it safer on its trip between computers. 
• The technology is based on the essentials of secret codes, augmented by modern mathematics that protects our data in powerful ways.

Internet Security 

• Internet Security - measures to protect data during their transmission over a collection of interconnected networks Security Attacks, Services and Mechanisms
• To assess the security needs of an organization effectively, the manager responsible for security needs some systematic way of defining the requirements for security and characterization of approaches to satisfy those requirements. 
• One approach is to consider three aspects of information security:
• Security attack – Any action that compromises the security of information owned by an organization.
• Security mechanism – A mechanism that is designed to detect, prevent or recover from a security attack.
• Security service – A service that enhances the security of the data processing systems and the information transfers of an organization. The services are intended to counter security attacks and they make use of one or more security mechanisms to provide the service. 

Security Services

The classification of security services are as follows

Confidentiality

• Ensures that the information in a computer system a n d transmitted information are accessible only for reading by authorized parties.
• E.g. Printing, displaying and other forms of disclosure.

Authentication 

• Ensures that the origin of a message or electronic document is correctly identified, with an assurance that the identity is not false.

Integrity

• It ensures that only authorized parties are able to modify computer system assets and transmitted information. 
• Modification includes writing, changing status, deleting, creating and delaying or replaying of transmitted messages.

Non repudiation 

• It requires that neither the sender nor the receiver of a message will be able to deny the transmission of data.

Access control

• It requires that access to information resources may be controlled by or the target system on the basis of authentication.

Availability

• It requires that computer system assets(System and its services) be available to authorized parties when needed.