Examples of security in the real world include locks on doors, alarms in our cars, or security staff including police. While this is a broad term that could even refer to protecting a computer from physical theft, we usually use it to describe methods of protecting confidential information stored on a computer. Increasing your own knowledge is your best defense. As you learn the practical information about how computer criminals gain unauthorized access, you can employ better means of protection. Information about you including financial information and account numbers, medical history, race, and marital status is probably stored on computing equipment somewhere.
Most organizations have their computing equipment connected to the Internet.
Any functionality that you have using a computer can potentially be exploited. Internet connected computers have bugs and features that can be exploited by remote computers. In some cases this means someone impersonating you electronically, or in other cases depriving others from access which is called denial of service. Denial of service attacks are the electronic equivalent of vandalism. This is a practical example of what we can do to protect the integrity of our systems.