The word security can mean different things when taken in different contexts. For instance, we talk about security in relation to national policy, personal safety, financial risk, and privacy of communication. We even use the word to describe our state of emotions. So what is the common thread that links these definitions? Why do we use the same word to describe protection from muggers and protection from hackers?
We propose to define security in the context of two groups: "the good guys" and the "bad guys." It doesn't matter if we are talking about people, robots, or computers; in our definition, if there are no "bad guys," you are secure by default. Imagine a perfect world with no crime there would be no need for a police force. Security tries to create such a perfect world, not globally but in a controlled space; it tries to create a bubble within which there are no "bad guys" at a given time. National security performs this role for a country, personal security for the living space of an individual, and emotional security for the confines of a person's mind. If the security is implemented successfully, the entity being secured is immune from the influence of the "bad guys." It is as though the bad guys don't exist.
As we look at Wi-Fi security, keep this goal in mind: Make it as though the bad guys don't exist. It is dangerous to focus on only one mechanism of security, such as data encryption, or to concentrate on defending against a certain type of attack. Also, it is wrong to ignore security weaknesses just because they have low consequences. Suppose a virus succeeds in getting into your computer, but it does no damage. Would we say security hasn't been breached because no damage was done? No, because although there is no consequence, we still have a security breach. In the same way, solutions for Wi-Fi LAN security should prevent any sort of interference with, or monitoring of, your actions. This is the ultimate goal of security.
With the new Wi-Fi security measures covered in this book, we can come close to this ultimate security goal. There is only one thing we cannot achieve because we are using wireless. Someone can prevent your communications by transmitting a jamming signal; in other words, the bad guys will still be able to demonstrate their presence by blocking communication. But if we design our security protocols correctly, and install them correctly, that is all they can do.