Computer hacker is any skilled computer expert who uses his technical knowledge to solve problems. Although "hacker" can refer to any skilled computer programmer, the term has been associated with "security hacker" in popular culture. With its technical knowledge, security hacker uses errors or loopholes to invade computer system.

There are four main motivations for hackers to try to break into computers and networks. First of all, stealing credit card numbers or manipulating the banking system in the hacker system will bring criminal financial benefits. Secondly, many hackers survive in the process of improving their reputation in hacker subculture, and will put their own handle on the defaced website, or leave other evidences to prove that they are involved in specific hacker activities. Third, corporate espionage enables companies to obtain information about products or services that may be stolen or used as market leverage. Fourth, the attacks supported by the state provide the nation-state with the choice of wartime and intelligence collection in, or through cyberspace.

Today, because of the use of the term in the mass media since the 1980s, the mainstream use of "hacker" mainly refers to computer criminals. This includes what hackers call "script boy". People use other people's programs to break into the computer and have little knowledge of the way they work. This usage has become so common that the public is largely unaware of the existence of different meanings. [2] Although amateurs are usually called hackers, computer security hackers have recognized and accepted hackers, but people from programming subculture think that the usage related to computer intrusion is incorrect, and emphasize the difference between the two by calling security circuit breakers "hackers" (similar to security biscuits).

Controversy is often based on the saying that the word originally refers to someone messing up something with a positive meaning, that is, using naughty intelligence to achieve a goal. However, it is speculated that the meaning of the term has changed in the past few decades and refers to computer criminals.

With the wide spread of safety related usage, its original meaning has become less known. In today's popular usage and media, "computer intruder" or "computer criminal" is the exclusive meaning of today's words. (for example, "Internet hackers" broke through state security systems in March. ") In the computer enthusiast (hacker culture) community, the main meaning is a supplementary description of a particularly outstanding programmer or technical expert. (for example, "Linux creator Linus Torvalds is seen by some as a hacker.") A large part of the technology community insists that the latter is the "right" use of words (see glossary definitions below).

The current use of the term by mainstream media dates back to the early 1980s. When the mainstream media introduced the term to a broader society in 1983, even people in the computer community called computer intrusion "hacker", although it was not the exclusive definition of the term. As the media use more and more terms with criminal meaning, the computer industry began to distinguish their terms. In order to maintain the distinction between "hackers" in the legitimate programmer community and hackers who perform computer intrusions, we have created alternative terms such as "cracker". When the law against computer intrusion came into force, terms such as "black hat", "white hat" and "gray hat" appeared to distinguish criminal activities from legal activities.