Model for Network Security

Network Security Model:- 

           A message is to be transferred from one party to another across some sort of Internet service. The two parties, who are the principals in this transaction, must cooperate for the exchange to take place. A logical information channel is established by defining a route through the Internet from source to destination and by the cooperative use of communication protocols (e.g., TCP/IP) by the two principals.

Security aspects come into play when it is necessary or desirable to protect the information transmission from an opponent who may present a threat to confidentiality, authenticity, and so on. All the techniques for providing security have two components:

•  A security-related transformation on the information to be sent. Examples include the encryption of the message, which scrambles the message so that it is unreadable by the opponent, and the addition of a code based on the contents of the message, which can be used to verify the identity of the sender.

•  Some secret information shared by the two principals and, it is hoped, unknown to the opponent. An example is an encryption key used in conjunction with the transformation to scramble the message before transmission and unscramble it on reception.

 A trusted third party may be needed to achieve secure transmission. For example, a third party may be responsible for distributing the secret information to the two principals while keeping it from any opponent. Or a third party may be needed to arbitrate disputes between the two principals concerning the authenticity of a message transmission.

This general model shows that there are four basic tasks in designing a particular security service:

1.  Design an algorithm for performing the security-related transformation. The algorithm should be such that an opponent cannot defeat its purpose.

2.  Generate the secret information(keys) to be used with the algorithm.

3.  Develop methods for the distribution and sharing of the secret information.

4.  Specify a protocol to be used by the two principals that makes use of the security algorithm and the secret information to achieve a particular security service.

using this model requires us to: 

• select appropriate gatekeeper functions to identify users 
• implement security controls to ensure only authorized users access designated information or resources