Phrack is an e-zine written by and for hackers, first published November 17, 1985. It had a wide circulation which included both hackers and computer security professionals.

A security hacker is someone who explores methods for breaching defenses and exploiting weaknesses in a computer system or network. Hackers may be motivated by a multitude of reasons, such as profit, protest, information gathering, challenge, recreation, or evaluation of a system weaknesses to assist in formulating defenses against potential hackers.