TABLE OF CONTENTS Network security is a very broad term. In its fullest sense, it means protecting data that are stored on or that travel over a network against both accidental and intentional unauthorized disclosure or modification. The most often overlooked part of this definition is that it includes accidental occurrences, such as an inadequately debugged application program that damages data.
Another way to look at security is to consider the difference between security and privacy. Privacy is the need to restrict access to data, whether it be trade secrets or personal information that by law must be kept private. Security is what you do to ensure privacy.
Many people view network security as having three goals:
Confidentiality: Ensuring that data that must be kept private, stay private.
Integrity: Ensuring that data are accurate. For a security professional, this means that data must be protected from unauthorized modification and/or destruction.
Availability: Ensuring that data are accessible whenever needed by the organization. This implies protecting the network from anything that would make it unavailable, including such events as power outages.
