Learn how to use good hacking to prevent your system from becoming the victim of attacks! "The Unofficial Guide to Ethical Hacking, Second Edition" defines the difference between hackers - those who crack a computer system for the sheer challenge of doing so - and crackers - an elusive class of computer criminals who break into systems, release viruses, and deface Web sites. Ethical hackers often help out system administrators by notifying them of loopholes in their systems before crackers can get to them and cause damage. More than just a guide to hacking, this book explores all aspects of computer security in a hands-on and easy-to-comprehend manner - a must-read for any computer user who wants to learn how a system is cracked and how you can better protect yourself. With helpful resources and clear, step-by-step instructions on various hacking techniques, this book features the most up-to-date and comprehensive information and methods, covering file encryption, firewalls, and viruses, as well as new topics such as instant messenger hacking, intellectual property thefts, identity attacks, and much more.