Design and implementation of network security

The requirements of information security within an organization have undergone two major changes in the last several decades before the widespread use of data processing equipment the security of information felt to be valuable to an organization was provided primarily by physical and administrative means with the introduction of computer the need for automated tools for protecting files and other information stored on the computer became an evident .this is especially the case for a shared system such as time sharing system and the need is even more acute for systems that can be accessed for a public telephone or a data network the generic name for the collection of tools to protect data and to thwart hackers is ―computer security‖. 

Network Security is a broad topic and covers a multitude of sins. In its simplest form, it is concerned with making sure that nosy people cannot read, or worse yet, secretly modify messages intended for other recipients. It is concerned with people trying to access remote services that they are not authorized to use. Most security problems are intentionally caused by malicious people trying to gain some benefit, get attention, or to harm someone. Network security problems can be divided roughly into four closely intertwined areas: secrecy, authentication, non repudiation, and integrity control. Secrecy, also called confidentiality, has to do with keeping information out of the hands of unauthorized users. This is what usually comes to mind when people think about network security. Authentication deals with determining whom you are talking to before revealing sensitive information or entering into a business deal. Non repudiation deals with signatures.