Hacker

One who uses detailed knowledge of the internet to break through security barriers and examine, change,or steal information stored on computer systems. Criminal-hackers, who are sometimes called “crackers", may commit credit fraud, steal identities, and release viruses or worms. To "phreak” is to illegally access telephone systems and other lines of communication. To "crack" software is to bypass security codes, which prevent piracy by non-paying users. The "hacktivist" works for a social or ideological cause. Black-hat hackers are those who work maliciously, whereas white-hat hackers usually refers to hackers with an ethical cause. Within the hacker communities there are various levels of expertise, ranging from breaking security systems to the expansion of software and hardware. The Guru and the Wizard also exist, the first being a highly expert hacker who also teaches those who do not know how to hack, and the second being only a highly expert hacker. When first used the term hacker was taken in a favorable sense, meaning deeply expert.