Information security is concerned with three main areas:
1) Confidentiality: Information should be available only to those who rightfully have access to it.
2) Integrity: Information should be modified only by those who are authorized to do so.
3) Availability: Information should be accessible to those who need it when they need it. These concepts apply to home Internet users just as much as they would to any corporate or government network.
You probably wouldn’t let a stranger look through your important documents. In the same way, you may want to keep the tasks you perform on your computer confidential, whether it’s tracking your investments or sending email messages to family and friends. Also, you should have some assurance that the information you enter into your computer remains intact and is available when you need it. Some security risks arise from the possibility of intentional misuse of your computer by intruders via the Internet. Others are risks that you would face even if you weren’t connected to the Internet (e.g. hard disk failures, theft, power outages). The bad news is that you probably cannot plan for every possible risk. The good news is that you can take some simple steps to reduce the chances that you’ll be affected by the most common threats. These steps help with both the intentional and accidental risks you’re likely to face.