From the very first chapter this book has been about how computer scientists think. Unfortunately, a few computer scientists use their skills to do harm. The problem is that just as computing technology can be used to solve our problems, so too it can be used to steal or vandalize. It is this possibility for abuse of technology that has elevated the importance of computer-related security.
The topic of security is in reality a modern struggle between good and evil. Computational thinking is employed by those trying to attack others via the Internet. Computational thinking is also used to construct security systems that counter such threats, and all of us need to think computationally for our own protection in this age of technology.