Computer intrusion

A security hacker is someone who seeks to breach defenses and exploit 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 to evaluate system weaknesses to assist in formulating defenses against potential hackers. The subculture that has evolved around hackers is often referred to as the computer underground.

There is a longstanding controversy about the term's true meaning. In this controversy, the term hacker is reclaimed by computer programmers who argue that it refers simply to someone with an advanced understanding of computers and computer networks, and that cracker is the more appropriate term for those who break into computers, whether computer criminal (black hats) or computer security expert (white hats). A 2014 article concluded that "... the black-hat meaning still prevails among the general public".

In computer security, a hacker is someone who focuses on security mechanisms of computer and network systems. While including those who endeavor to strengthen such mechanisms, it is more often used by the mass media and popular culture to refer to those who seek access despite these security measures. That is, the media portrays the 'hacker' as a villain. Nevertheless, parts of the subculture see their aim in correcting security problems and use the word in a positive sense. White hat is the name given to ethical computer hackers, who utilize hacking in a helpful way. White hats are becoming a necessary part of the information security field. They operate under a code, which acknowledges that breaking into other people's computers is bad, but that discovering and exploiting security mechanisms and breaking into computers is still an interesting activity that can be done ethically and legally. Accordingly, the term bears strong connotations that are favorable or pejorative, depending on the context.

The subculture around such hackers is termed network hacker subculture, hacker scene, or computer underground. It initially developed in the context of phreaking during the 1960s and the microcomputer BBS scene of the 1980s. It is implicated with 2600: The Hacker Quarterly and the alt.2600 newsgroup.

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