This document discusses ethical hacking and defines different types of hackers. It begins by defining ethical hacking as testing systems for security purposes with permission. Hacking is then differentiated from cracking, with cracking defined as malicious hacking for personal gain which is illegal. The document outlines different types of hackers including white hat, black hat, and grey hat hackers. It provides examples of script kiddies and hackers with genuine licenses. Security measures are recommended to prevent hacking like using antiviruses and strong passwords. In conclusion, some notable hackers from history are named.