Hacker

A hacker is typically described as an individual who has a high level of skill with a computer that uses their technical knowledge to complete tasks and problems. Usually hackers have a bad connotation to them, but there are two main types of hackers.

White hat hackers use their technical skills ethically. These individuals are employed by companies and the government to ensure that their networks do not have any security vulnerabilities. This is known as penetration testing, or "pentesting" for short. White hat hackers ensure that any information that should be encrypted in a system is truly secure.

Black hat hackers are the type of individuals that most people think of when they hear the term "hacker". These are the types that are typically presented as the antagonist in television shows or movies. Black hat hackers are criminals because they attempt to access users' private data illegally using their technical skills. They also attempt to spread malware and execute various other cyber attacks.

References:
 * 1) What is hacker? - Definition from WhatIs.com. (n.d.). Retrieved April 15, 2018, from https://searchsecurity.techtarget.com/definition/hacker