Copy protection
Copy protection, also known as content protection, copy prevention and copy restriction, describes measures to enforce copyright by preventing the reproduction of software, films, music, and other media. Copy protection is most commonly found on videotapes, DVDs, Blu-ray discs, HD-DVDs, computer software discs, video game discs and cartridges, audio CDs and some VCDs. Some methods of copy protection have also led to criticisms because it caused inconvenience for paying consumers, or it secretly installed additional or unwanted software to detect copying activities on the consumer's computer. Making copy protection effective while protecting consumer rights remains  a problem with media publication. Terminology. Media corporations have always used the term copy protection, but critics argue that the term tends to sway the public into identifying with the publishers, who favor restriction technologies, rather than with the users. Copy prevention and copy control may be more neutral terms. "Copy protection" is a misnomer for some systems, because any number of copies can be made from an original and all of these copies will work, but only in one computer, or only with one dongle, or only with another device that cannot be easily copied. The term is  also often related to, and confused with, the concept of digital rights management. Digital rights management is a more general term because it includes all sorts of management of works, including copy restrictions. Copy protection may include measures that are not digital. A more appropriate term may be "technological protection measures" (TPMs), which is often defined as the use of technological tools in order to restrict the use or access to a work. Business rationale. Unauthorized copying and distribution accounted for $2.4 billion in lost revenue in the United States alone in the 1990s, and is assumed to be  causing impact on revenues in the music and the video game industry, leading to proposal of stricter copyright laws such as PIPA. Copy protection is most commonly found on videotapes, DVDs, computer software discs, video game discs and cartridges, audio CDs and some VCDs. Many media formats are easy to copy using a machine, allowing consumers to distribute copies to their friends, a practice known as "casual copying". Companies publish works under copyright protection because they believe that the cost of implementing the copy protection will be less than the revenue produced by consumers who buy the product instead of  acquiring it through casually copied media. Opponents of copy protection argue that people who obtain free copies only use what they can get for free and would not purchase their own copy if they were unable to obtain a free copy. Some even argue that free copies increase profit; people who receive a free copy of a music CD may then go and buy more of that band's music, which they would not have done otherwise. Some publishers have avoided copy-protecting their products on the theory that the resulting inconvenience to their users outweighs any benefit of frustrating  casual copying. From the perspective of the end user, copy protection is always a cost. DRM and license managers sometimes fail, are inconvenient to use, and may not afford the user all of the legal use of the product they have purchased. The term "copy protection" refers to the technology used to attempt to frustrate copying, and not to the legal remedies available to publishers or authors whose copyrights are violated. Software usage models range from node locking to floating licenses (where a fixed number licenses can be concurrently used across an enterprise), grid computing (where multiple computers function as  one unit and so use a common license) and electronic licensing (where features can be purchased and activated online). The term "license management" refers to broad platforms which enable the specification, enforcement and tracking of software licenses. To safeguard copy protection and license management technologies themselves against tampering and hacking, software anti-tamper methods are used. Floating licenses are also being referred to as "Indirect Licenses", and are licenses that at the time they are issued, there is no actually user who will use them. That has some technical influence over some of their characteristics. "Direct Licenses" are issued after  a certain user requires it. As an example, an activated Microsoft product, contains a "Direct License" which is locked to the PC where the product is installed. From business standpoint, on the other hand, some services now try to monetize on additional services other than the media content so users can have better experience than simply obtaining the copied product. Technical challenges. From a technical standpoint, it seems impossible to completely prevent users from making copies of the media they purchase, as long as a "writer" is available that can write to blank media. All types of media require a  player—a CD player, DVD player, videotape player, computer or video game console—which must be able to read the media in order to display it to a human. Logically, a player could be built that reads the media and then writes an exact copy of what was read to the same type of media. At a minimum, digital copy protection of non-interactive works is subject to the analog hole: regardless of any digital restrictions, if music can be heard by the human ear, it can also be recorded (at the very least, with a microphone and tape recorder); if  a film can be viewed by the human eye, it can also be recorded (at the very least, with a video camera and recorder). In practice, almost-perfect copies can typically be made by tapping into the analog output of a player (e.g. the speaker output or headphone jacks) and, once redigitized into an unprotected form, duplicated indefinitely. Copying text-based content in this way is more tedious, but the same principle applies: if it can be printed or displayed, it can also be scanned and OCRed. With basic software and some patience, these techniques can be applied by a  typical computer-literate user. Since these basic technical facts exist, it follows that a determined individual will definitely succeed in copying any media, given enough time and resources. Media publishers understand this; copy protection is not intended to stop professional operations involved in the unauthorized mass duplication of media, but rather to stop "casual copying". Copying of information goods which are downloaded (rather than being mass-duplicated as with physical media) can be inexpensively customized for each download, and thus restricted more effectively, in a process known as "traitor tracing". They can be encrypted in a fashion which is unique  for each user's computer, and the decryption system can be made tamper-resistant. Methods. For information on individual protection schemes and technologies, see List of copy protection schemes or relevant category page. Computer software. Copy protection for computer software, especially for games, has been a long cat-and-mouse struggle between publishers and crackers. These were (and are) programmers who defeated copy protection on software as a hobby, add their alias to the title screen, and then distribute the "cracked" product to the network of warez BBSes or Internet sites that specialized in distributing unauthorized copies of software. Early  ages. When computer software was still distributed in audio cassettes, audio copying was unreliable, while digital copying was time consuming. Software prices were comparable with audio cassette prices. To make digital copying more difficult, many programs used non-standard loading methods (loaders incompatible with standard BASIC loaders, or loaders that used different transfer speed). Unauthorized software copying began to be a problem when floppy disks became the common storage media. The ease of copying depended on the system; Jerry Pournelle wrote in "BYTE" in 1983 that "CP/M doesn't lend itself to copy protection" so its users "haven't  been too worried" about it, while "Apple users, though, have always had the problem. So have those who used TRS-DOS, and I understand that MS-DOS has copy protection features". 1980s Locksmith. Pournelle disliked copy protection and, except for games, refused to review software that used it. He did not believe that it was useful, writing in 1983 that "For every copy protection scheme there's a hacker ready to defeat it. Most involve so-called nibble/nybble copiers, which try to analyze the original disk and then make a copy". IBM's Don Estridge agreed: "I guarantee that  whatever scheme you come up with will take less time to break than to think of it." While calling piracy "a threat to software development. It's going to dry up the software", he said "It's wrong to copy-protect programs ... There ought to be some way to stop [piracy] without creating products that are unusable." Copy protection sometimes caused software to not run on clones, such as the Apple II-compatible Laser 128. The back and forth struggle between copy protection engineers and nibble copiers continued until the Apple II became obsolete and was replaced by the IBM  PC and its clones. In 1989 Gilman Louie, head of Spectrum Holobyte, stated that copy protection added about $0.50 per copy to the cost of production of a game. Other software relied on complexity; "Antic" in 1988 observed that "WordPerfect" for the Atari ST "is almost unusable without its manual of over 600 pages!". (The magazine was mistaken; the ST version was so widely pirated that the company threatened to discontinue it.) To limit reusing activation keys to install the software on multiple machines, it has been attempted to tie the installed software to a specific machine by involving  some unique feature of the machine. Serial number in ROM could not be used because some machines do not have them. Some popular surrogate for a machine serial number were date and time (to the second) of initialization of the hard disk or MAC address of Ethernet cards (although this is programmable on modern cards). With the rise of virtualization, however, the practice of locking has to add to these simple hardware parameters to still prevent copying. Early video games. During the 1980s and 1990s, video games sold on audio cassette and floppy disks were sometimes protected with an external  user-interactive method that demanded the user to have the original package or a part of it, usually the manual. Copy protection was activated not only at installation, but every time the game was executed. Several imaginative and creative methods have been employed, in order to be both fun and hard to copy. These include: All of these methods proved to be troublesome and tiring for the players, and as such greatly declined in usage by the mid-1990s, at which point the emergence of CDs as the primary video game medium made copy protection largely redundant, since CD copying technology  was not widely available at the time. Some game developers, such as Markus Persson, have encouraged consumers and other developers to embrace the reality of unlicensed copying and utilize it positively to generate increased sales and marketing interest. Videotape. Starting in 1985 with the video release of "The Cotton Club" (Beta and VHS versions only), Macrovision licensed to publishers a technology that exploits the automatic gain control feature of VCRs by adding pulses to the vertical blanking sync signal. These pulses do not affect the image a consumer sees on their TV, but do confuse the recording-level circuitry of  consumer VCRs. This technology, which is aided by U.S. legislation mandating the presence of automatic gain-control circuitry in VCRs, is said to "plug the analog hole" and make VCR-to-VCR copies impossible, although an inexpensive circuit is widely available that will defeat the protection by removing the pulses. Macrovision had patented methods of defeating copy prevention, giving it a more straightforward basis to shut down manufacture of any device that descrambles it than often exists in the DRM world. While used for pre-recorded tapes, the system was not adopted for television broadcasts; Michael J. Fuchs of HBO  said in 1985 that Macrovision was "not good technology" because it reduced picture quality and consumers could easily bypass it, while Peter Chernin of Showtime said "we want to accommodate our subscribers and we know they like to tape our movies". Notable payloads. Over time, software publishers (especially in the case of video games) became creative about crippling the software in case it was duplicated. These games would initially show that the copy was successful, but eventually render themselves unplayable via subtle methods. Many games use the "code checksumming" technique to prevent alteration of code to bypass other copy protection . Important constants for the game - such as the accuracy of the player's firing, the speed of their movement, etc. - are not included in the game but calculated from the numbers making up the machine code of other parts of the game. If the code is changed, the calculation yields a result which no longer matches the original design of the game and the game plays improperly. "Copying commercial games, such as this one, is a criminal offense and copyright infringement." "Copying and re-supplying games such as this one can lead to a term of imprisonment." Think of a  pirated game as stolen property. "This game is protected by the FADE system. You can play with a pirated game- but not for long. The quality of a pirated game will degrade over time." "Purchase only genuine software at legitimate stores." The usage of copy protection payloads which lower playability of a game without making it clear that this is a result of copy protection is now generally considered unwise, due to the potential for it to result in unaware players with unlicensed copies spreading word-of-mouth that a game is of low quality. The authors of FADE explicitly  acknowledged this as a reason for including the explicit warning message. Anti-piracy. Anti-piracy measures are efforts to fight against copyright infringement, counterfeiting, and other violations of intellectual property laws. It includes, but is by no means limited to, the combined efforts of corporate associations (such as the RIAA and MPAA), law enforcement agencies (such as the FBI and Interpol), and various international governments to combat copyright infringement relating to various types of creative works, such as software, music and films. These measures often come in the form of copy protection measures such as DRM, or measures implemented through  a content protection network, such as Distil Networks or Incapsula. Richard Stallman and the GNU Project have criticized the use of the word "piracy" in these situations, saying that publishers use the word to refer to "copying they don't approve of" and that "they [publishers] imply that it is ethically equivalent to attacking ships on the high seas, kidnapping and murdering the people on them". Certain forms of Anti-Piracy (such as DRM), are considered by consumers to control the use of the products content after sale. In the case "MPAA v. Hotfile", Judge Kathleen M. Williams granted a  motion to deny the prosecution the usage of words she views as "pejorative". This list included the word "piracy", the use of which, the motion by the defense stated, would serve no purpose but to misguide and inflame the jury. The plaintiff argued the common use of the terms when referring to copyright infringement should invalidate the motion, but the Judge did not concur. Anti-piracy in file sharing. Today copyright infringement is often facilitated by the use of file sharing. In fact, infringement accounts for 23.8% of all internet traffic in 2013. In an effort to cut down on  this, both large and small films and music corporations have issued DMCA takedown notices, filed lawsuits, and pressed criminal prosecution of those who host these file sharing services.