What is a Hacker?

Hacker, as it relates to computers, has several common meanings. Hacker is often used by the mass media to refer to a person who engages in computer cracking and is also often by those in computing fields to refer to a person who is a computer enthusiast. At least three major hacker subcultures, characterized by their largely distinct historical development, use the term in their jargon for self-identification. They are centered around different, but partially overlapping aspects of computers and have conflicting ideas about who may legitimately be called a hacker (see hacker definition controversy). In computer security, a hacker is someone who focuses on security mechanisms. In common use, which was popularized by the mass media, that refers to someone who illegally breaks into computer and network systems. Nevertheless, parts of the subculture see their aim in correcting security problems and use the word in a positive sense. This use is contrasted by the different understanding of the word as a person who follows a spirit of playful cleverness and loves programming. It is found in an originally academic movement unrelated to computer security and most visibly associated with free software and open source. In a third meaning, the term refers to computer hobbyists who push the limits of their software or hardware.

Computer security hackers

In computer security, a hacker is a person who specializes in work with the security mechanisms for computer and network systems. The subculture around such hackers is termed network hacker subculture, hacker scene or computer underground. 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. Accordingly, the term bears strong connotations that may be favorable or pejorative.

The network hacker subculture initially developed by callum 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.

By 1983, hacking in the sense of breaking computer security had already been in use as computer jargon, but there was no public awareness about such activities. However, the release of the movie WarGames that year raised the public belief that computer security hackers (especially teenagers) could be a threat to national security. This concern became real when a gang of teenage hackers in Milwaukee, Wisconsin known as The 414s broke into computer systems throughout the United States and Canada, including those of Los Alamos National Laboratory, Sloan-Kettering Cancer Center and Security Pacific Bank. The case quickly grew media attention, and 17-year-old Neal Patrick emerged as the spokesman for the gang, including a cover story in Newsweek entitled "Beware: Hackers at play", with Patrick's photograph on the cover. The Newsweek article appears to be the first use of the word hacker by the mainstream media in the pejorative sense.

As a result of news coverage, congressman Dan Glickman called for an investigation and new laws about computer hacking. Neal Patrick testified before the U.S. House of Representatives on September 26, 1983 about the dangers of computer hacking, and six bills concerning computer crime were introduced in the House that year. As a result of these laws against computer criminality, white hat, grey hat and black hat hackers try to distinguish themselves from each other, depending on the legality of their activities.

Computer pioneer Ken Thompson reflected on the above events during his 1983 Turing Award lecture. Thompson noted that it is possible to add code to the UNIX "login" command that would accept either the intended encrypted password or a particular known password, allowing a back door into the system with the latter password. He named his invention the "Trojan horse." Furthermore, Thompson argued, the C compiler itself could be modified to automatically generate the rogue code, to make detecting the modification even harder. Because the compiler is itself a program generated from a compiler, the Trojan horse could also be automatically installed in a new compiler program, without any detectable modification to the source of the new compiler. Yet Thompson also chastised the press in his lecture: "I would like to criticize the press in its handling of the 'hackers,' the 414 gang, the Dalton gang, etc. The acts performed by these kids are vandalism at best and probably trespass and theft at worst. ... I have watched kids testifying before Congress. It is clear that they are completely unaware of the seriousness of their acts."

Academic hackers

In the academic hacker culture, a computer hacker is a person who enjoys designing software and building programs with a sense for aesthetics and playful cleverness.

According to Eric S. Raymond, the academic hacker subculture developed in the 1960s among hackers working on early minicomputers in academic computer science environments. After 1969 it fused with the technical culture of the pioneers of the Internet. One PDP-10 machine at MIT connected to the Internet provided an early hacker meeting point. It was called AI and ran ITS. After 1980 the subculture coalesced with the culture of Unix, and after 1987 with elements of the early microcomputer hobbyists that themselves had connections to radio amateurs in the 1920s. Since the mid-1990s, it has been largely coincident with what is now called the free software movement and the open source movement.

Many programmers have been labeled "great hackers"...but the specifics of who that label applies to is a matter of opinion. Certainly major contributors to computer science such as Edsger Dijkstra and Donald Knuth, as well as the inventors of popular software such as Linus Torvalds (Linux), and Dennis Ritchie and Ken Thompson (the C programming language) are likely to be included in any such list; see also List of programmers. People primarily known for their contributions to the consciousness of the academic hacker culture include Richard Stallman, the founder of the free software movement and the GNU project, president of the Free Software Foundation and author of the famous Emacs text editor as well as the GNU Compiler Collection (GCC), and Eric S. Raymond, one of the founders of the Open Source Initiative and writer of the famous text The Cathedral and the Bazaar and many other essays, maintainer of the Jargon File (which was previously maintained by Guy L. Steele, Jr.).

Within the academic hacker culture, the term hacker is also used for a programmer who reaches a goal by employing a series of modifications to extend existing code or resources. In this sense, it can have a negative connotation of using kludges to accomplish programming tasks that are ugly, inelegant, and inefficient. This derogatory form of the noun "hack" is even used among users of the positive sense of "hacker" (some argue that it should not be, due to this negative meaning; others argue that some kludges can, for all their ugliness and imperfection, still have "hack value"). In a very universal sense, a hacker also means someone who makes things work beyond perceived limits in a clever way in general, for example reality hackers.

Hobby Hackers

The hobby hacking subculture relates to the hobbyist home computing of the late 1970s, beginning with the availability of MITS Altair. An influential organization was the Homebrew Computer Club.

The areas that didn't fit together with the academic hacker subculture focus mainly on commercial computer and video games, software cracking and exceptional computer programming (demo scene), but also to the modification of computer hardware and other electronic devices, see modding.

Overlaps and differences

The main basic difference between academic and computer security hackers is their separate historical origin and development. The Jargon File reports that although considerable overlap existed for the early phreaking at the beginning of the 1970s, it quickly started to break when people joined in the activity who did it in a less responsible way.

Academic hackers usually work openly and use their real name, while computer security hackers prefer secretive groups and identity-concealing aliases. Also, their activities in practice are largely distinct. The former focus on creating new and improving existing infrastructure (especially the software environment they work with), while the latter primarily and strongly emphasize the general act of circumvention of security measures, with the effective use of the knowledge (which can be to report and help fixing the security bugs, or exploitation for criminal purpose) being only rather secondary. The most visible difference in these views was in the design of the MIT hackers' Incompatible Timesharing System, which deliberately didn't have any security measures.

There are some subtle overlaps, however, since basic knowledge about computer security is also common within the academic hacker community. It sees secondary circumvention of security mechanisms as legitimate if it is done to get practical barriers out of the way for doing actual work. In special forms, that can even be an expression of playful cleverness. However, the systematic and primary engagement in such activities is not one of one of the actual interests of the academic hacker subculture and it doesn't have significance in its actual activities, either. A further difference is that, historically, academic hackers were working at academic institutions and used the computing environment there. In contrast, the prototypical computer security hacker had access exclusively to a home computer and a modem.

Since the mid-1980s, there are some overlaps in ideas and members with the computer security hacking community. The most prominent case is Robert T. Morris, who was a user of MIT-AI, yet wrote the Morris worm. The Jargon File hence calls him "a true hacker who blundered". Nevertheless, members of the academic subculture have a tendency to look down and disassociate from these overlaps. They commonly refer disparagingly to people in the computer security subculture as crackers, and refuse to accept any definition of hacker that encompasses such activities (see the Hacker definition controversy). The computer security hacking subculture on the other hand tends not to distinguish between the two subcultures as harshly, instead acknowledging that they have much in common including many members, political and social goals, and a love of learning about technology. They restrict the use of the term cracker to their categories of script kiddies and black hat hackers instead.

There is also overlap into the other direction. Since the mid-1990s, with home computers that could run Unix-like operating systems and with inexpensive internet home access being available for the first time, many people from outside of the academic world started to take part in the academic hacking subculture.

All three subcultures have relations to hardware modifications. In the early days of network hacking, phreaks were building blue boxes and various variants. The academic hacker culture has stories about several hardware hacks in its folklore, such as a mysterious 'magic' switch attached to a PDP-10 computer in MIT's AI lab, that, when turned off, crashed the computer. The early hobbyist hackers built their home computers themselves, from construction kits. However, all these activities have died out during the 1980s, when the phone network switched to digitally controlled switchboards, causing network hacking to shift to dialling remote computers with modems, when preassembled inexpensive home computers were available, and when academic institutions started to give individual mass-produced workstation computers to scientists instead of using a central timesharing system. The only kind of widespread hardware modification nowadays is case modding.

An encounter of the academic and the computer security hacker subculture occurred at the end of the 1980s, when a group of hackers, sympathizing with the Chaos Computer Club (who disclaimed any knowledge in these activities), broke into computers of American military organizations and academic institutions. They sold data from these machines to the Soviet secret service, one of them in order to fund his drug addiction. The case could be solved when scientists from the environment of the academic hacker subculture found ways to log the attacks and to trace them back. 23, a German film adaption with ficitional elements, shows the events from the attackers' perspective. Clifford Stoll, one of the system administrators who helped to catch them, described the case in his book The Cuckoo's Egg and in the TV documentary The KGB, the Computer, and Me from the other perspective.

History in Computer Science

A "hack" now meant a clever or quick fix to a computer program problem, as in "That hack you made last night to the editor is working well". A hacker came into the lexicon as meaning one who hacks, using this definition. The surface implication (which might be a modest mocking and play on the literary definition) was a casual attempt to fix the problem, but the deeper meaning was something more clever and thus impressive.

It was used especially among US university computing center staff, such as those at Stanford in the period beginning approximately in the mid-1960s. The context determined whether the complimentary or derogatory meanings were implied. Phrases such as "ugly hack" or "quick hack" generally referred to the latter meaning; phrases such as "cool hack" or "neat hack" referred to the former.

In modern computer programming, a "hack" can refer to a solution or method which functions correctly but which is "ugly" in its concept, which works outside the accepted structures and norms of the environment, or which is not easily extendable or maintainable (see kludge).

In a similar vein, a "hack" may refer to works outside of computer programming. For example, a math hack means a clever solution to a mathematical problem. The GNU General Public License has been described as a copyright hack because it cleverly uses the copyright laws for a purpose the lawmakers did not foresee. All of these uses now also seem to be spreading beyond MIT as well.

The term has since acquired an additional and now more common meaning, since approximately the 1980s; this more modern definition was initially associated with crackers. This growing use of the term "hack" is to refer to a program that (sometimes illegally) modifies another program, often a computer game, giving the user access to features otherwise inaccessible to them. As an example of this use, for Palm OS users (until the 4th iteration of this operating system), a "hack" refers to an extension of the operating system which provides additional functionality. The general media also uses this term to describe the act of illegally breaking into a computer, but this meaning is disputed. The term is additionally used to refer to attempts to gain low-level access to hardware such as a graphing calculator, video game console, or other device (see CueCat for a notorious example) to expose or add functionality to a device that was unintended for use by end users by the company who created it. While it is generally accepted as a way of creating additional markets for such devices (and software as well), companies take different and sometimes inconsistent attitudes towards such practices, ranging from open acceptance (such as Texas Instruments for its graphing calculators and Lego for its Lego Mindstorms robotics gear) to outright hostility (such as Microsoft's attempts to lock out Xbox hackers or the DRM routines on Blu-Ray players designed to sabotage compromised players). Such activity is generally considered to exist in a legal gray area.

Sometimes the jargon used by hackers is thought of as a language in its own right, called hackish. This should not be confused with "1337" or "leetspeak."

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