Digital Rights Management (sometimes referred to as "digital restrictions management" or "digital rights mangling", especially among detractors, and usually abbreviated "DRM") is a general term for access control mechanisms implemented on digital media to limit what a user can and cannot do with it.
If you hear the word in general conversation, it's most likely specifically referring to the Copy Protection placed by copyright holders on digital audio and video files — restrictions on converting from one format to another, how many and what kinds of different devices the media can be played on, and so forth. One widespread example of this type of DRM is DVD Region Coding, which restricts playback of a DVD to a player marked with the same region code as the disc.
In the United States, the Digital Millennium Copyright Act outlaws the use of mechanisms for bypassing or circumventing DRM; other jurisdictions' laws vary.
The use of DRM is, to say the least, highly controversial. On the one hand, many large content groups (chief among them the RIAA, MPAA, IFPI, and video game distributors) argue that by preventing unauthorized copying, they ensure that artists are fairly compensated for their work and reduce the availability of illegal pirated content. On the other hand, a significant number of individuals and smaller entities (a number of indie record labels, for example) revile DRM as an infringement upon the user's own rights, such as fair use. Opponents seize on missteps like the infamous Sony "rootkit", which attempted to implement DRM on audio CDs by automatically installing software that opened computers to potential exploitation by malware.
What's perhaps proven the most relevant objection, though, is that DRMed files are usually just plain less useful. For instance, it's often impossible to transfer them from one device to another. That means it's actually more convenient to have an illegal file that some nice pirate has already stripped the DRM off of (which is exactly what happened to Assassins Creed 2, and why reviewers of that same game despised the "always online" requirement despite loving the game). All moral arguments one way or another aside, it became increasingly clear throughout the '00s that letting the pirates beat you on quality is just not good for business. This pure market logic is what has finally gotten many big companies who otherwise wholeheartedly embrace the thought behind DRM— like Apple and Amazon— to start migrating away from it. Not to mention the people who knew of this fact ten years before it even became so widespread.
Needless to say, reasoned discussion can be... difficult to come by, and much like the Console Wars, DRM as a subject of conversation is best avoided if you're not wearing a nice flame-proof jacket. An important issue with Digital Distribution, since there's no "physical" copy in the first place.
Not to be confused with "DRM Direct Rendering Manager, i.e. component supporting hardware acceleration" in Linux.
Types of DRM include:
Copy Protection - wherein measures are created to prevent users from copying floppies, CDs, DVDs, or other media.
Downloadable Content - in this case, in the sense that if you purchase a game pre-owned, you miss out on various portions of the game which were available to the original owner, unless you pay an 'access fee'.
So far the only DRM schema to avoid a ton of flak is Steam, but it's not without its vocal opponents and it launched to a shaky start. But aside from the initial online activation, Steam is fairly transparent and even comes with an "Offline Mode" in case there's no network connection so you can still play your games. The only problem is that Valve still allows third party DRM on top of Steam, but this is only a problem from the usual suspects.
A major point in their favor is the daily, twice-weekly, and quarterly sales, where games get marked down anywhere from 25-90% off, depending on the title.
Gears of War 2 was the largest game to initially implement the lattermost 'DLC' variety, with a pack of 5 remade multiplayer maps from the first game, but developers have irritably joked about doing the same thing with the endings of other games - which also, of course, makes them unwinnable to anyone without the ability to download the missing vital content.
Rock Band 2 is doing something similar — the manual includes a code that can be used to download 20 additional free songs (beyond the game's 84 on-disc), but the difference is that using this code is the only way to get the songs. (Unfortunately, this also means there's no way to get them in the Playstation 2 version of the game, which doesn't support DLC.) The same exact code (NOT the DLC code recieved after submitting it to Harmonix, the 20-character code on the back of the manual) is also used to get most of the licensed RB2 songs in Rock Band 3 (the ones from Harmonix-fronted bands were later released for free on the X360 and PS3)
Got Guitar Hero World Tour or Guitar Hero Smash Hits used? There's a good chance you won't be able to get any songs from them in Guitar Hero 5 (WITH all the new stuff added like Expert+ for GHWT drum charts) as a result of that, and you're guaranteed not to get them if you lack a manual. Oh, and you still have to pay for the re-licensing, but that's the least of the worries here.
The Nintendo Wii Speak microphone includes a single-use code to download the Wii Speak channel. Bought it used? No software for you!
Forza Motorsport 3 has an extra set of classic cars and test/benchmark circuits that you can download with the supplied code in the box.
SOCOM: U.S. Navy SEALs Fireteam Bravo 3 is the worst offender as of this writing. Bought it used? Pay an extra $20 to play online!
EA has been doing this too, most recently with the BioWare games Dragon Age and Mass Effect 2, which each come with a code for an extra party member if you buy them new (you must pay $15 for them if you buy it used). Mass Effect 2, however, has a little extra value with its Cerberus Network, which has various free bits of content, with more on the way, but you must either buy the game new or pay $15 for access to the network.
The WiiWare release of Mega Man 10 was hacked right after its release by dedicated fans, who discovered that several DLC packs (that constituted an extra character, returning bosses from previous games, and special stages) were already part of the coding (and that these DLC packs were already downloaded to your system when you bought the game). This meant that customers who bought the game had to pay an extra $10 to unlock content that was already made and on their systems. Naturally, this led to debates about the ethical nature of making customers pay for already-downloaded DLC.
Ditto Mass Effect 3 with its release-date DLC that you had to pay to unlock. A vocal segment of the fanbase views this as a blatant cash-grab on the part of EA and BioWare.
One of the earliest types and by far one of the most ineffective is the CD Key.
Microsoft Windows' Protected Media Path, to work with DRM-enabled media players.
Installation Limits, which prevent the game from being installed from the disk after it has been installed a few times.
SecuROM, which requires the CD to be in at all times when playing the game, although this can be defeated by either using a crack or (in some cases) making an ISO image of the game and mounting it.
Later versions of SecuROM added the above-mentioned Installation Limits in the worst possible ways. Multiple users on the same computer each counted as separate installs, and despite what marketing intended uninstalling the game would NOT raise your install limit number.
By far the most infamous one before SecuROM is StarForce. To sum it up, it installs a device driver with the highest security privileges (a Ring 0 driver), disables any SCSI device on your computer (most image mounting tools create a virtual SCSI drive), had a tendency to be unstable (which could crash the OS), Windows Vista was terribly allergic to it in normal mode (or even Safe Mode), and it left a huge security hole in your computer. This is all when it wasn't simply destroying your CD drive as a result of careless device commands. It also didn't uninstall even if you uninstalled the game that came with it.
Need more proof the StarForce developers are pond scum? When Stardock Software, creators of Galactic Civilizations and Sins of a Solar Empire, posted an article on their website stating how they felt that using DRM was bad customer relations and how they intended to abstain from adding DRM to any of their titles, StarForce responded by publishing torrent links to Stardock's games. That's right, they actively aided people in pirating the games of a company who refused to use their product. Whatever your feelings about piracy, to do something like that against a company who refuses to use your product out of a desire to please their customers just to teach some kind of warped lesson smacks of pettiness.
As if that wasn't enough, they threatened the first two parties that raised awareness of the damage StarForce can cause with a lawsuit, claiming that the FBI has already been notified. Because it's the FBI you usually call when somebody's defaming you.
Even better, it's becoming an established (and even accepted) practice for people to torrent a game as a sort of informal demo, and fork over money if they like what they see. All StarForce has provided is free advertising.
One of the earliest types of DRM is the infamous "What is word 20 on line 5 in page 30 of the instruction manual?" checks. If you lost the manual or obtained the game without one? You don't get to play! See the Copy Protection article for more information on these "feelies". If you have a copy of the manual's text that does not preserve the exact format of the original (i.e, a transcript instead of a scan of the original pages), then it will be a tedious trial and error ordeal to figure out which word it is.
Sierra spoofed this a bit with an age check "DRM" for its Leisure Suit Larry games, which simply asked a pop culture question that only an adult would probably know
One notable failure to enforce DRM in the music industry: Save an additional track to the disc, programmed and juxtaposed to convince computers the disc was blank. In order to render the disc playable on a computer, you'd have to render the track unreadable. Easier than it sounds, as the track was on the outermost edge, where it could easily be scratched or, more commonly, drawn over with a marker.
Sony attempted a disastrous DRM scheme in 2005 that upon inserting the disc into your drive, installed a rootkit onto computers and opened them up to much nastier computer problems. Soon, Sony was up to its ears in lawsuits and wound up having to recall all affected CDs. One affected Sony band, My Morning Jacket, encouraged fans to bypass the software and offered to replace affected CDs free of charge. That was months before Sony's full blown recall.
By late 2006-early 2007, the major labels eventually abandoned DRM on CDs because they wound up agreeing with critics that claimed it was punishing paying customers, who in many cases had decided to illegally download music when they otherwise would not because of DRM protection.
The FADE system uses fake scratches on the disc, which most copying programs automatically fix. The master program of the game itself checks for the bogus scratches' presence, and if they aren't there it cripples that game's features one by one.
Some floppy disk games used similar systems, either by using non-standard formatting or having laser-burned holes in the medium's surface. Direct copying of these disks left out the discrepancies which were detected by the program.
As per a stretch goal on the Kickstarter campaign, Obsidian Entertainment is leaving the DRM out of the hardcopy and GOG.com versions of Pillars of Eternity. You still need the DRM if you want the achievements, but that's just because those achievements are on Steam only, and their DRM is pretty unobtrusive anyway.
Starting with Starcraft II, new games by Blizzard Entertainment run on the "always online" principle: even if you want to play in the single-player mode, you still have to connect to Battle.net to do so, and if you can't connect now, tough luck. Starcraft II: Wings of Liberty still allowed one to play offline on a guest account once the copy had been "authorized" (which you had to do every time a patch had been applied), but with Heart of the Swarm that has been removed. You also no longer can run maps stored locally on your computer from the game itself — you now have to open the map in the editor, and select "Test Map".
A similar scheme is used by Electronic Arts with their Origin online store. If you purchased one of their newer games (such as Mass Effect 3 or the 2013 SimCity) through Origin, you won't be able to run it unless you are logged in.
Except EA in their infinite wisdom layers DRM on top of DRM. For instance, in Battlefield 3, the game doesn't launch from Origin. It launches from the Battlelog website. And Sim City (2013) requires an always-on connection. This proved to be disastrous at launch, with many people not being able to play the game at all thanks to it not even working.
At the Xbox One's reveal, gamers discovered that Microsoft was implementing new DRM restrictions on the console, such as requiring a once-a-day Internet connection and cutting off the console's game-playing functionality if it doesn't check in. There were also some highly controversial restrictions on used games. After massive backlash from gamers and some high-profile Take Thats by Sony at that year's E3, Microsoft abandoned these plans. What was worse was that their attempts to justify everything ended up making them look really bad, so not only did they have DRM that was wildly restrictive, but their responses to complaints were even worse than the DRM itself. One of the worst examples being when asked what should someone do if they just can't get an internet connection to their Xbox One, the reply was "Get an Xbox 360." Ouch.
Perhaps the most notable aversion in the '10s is CD Projekt RED, the developers of The Witcher series and masterminds behind GOG.com, who have eschewed DRM entirely in their own games and on the site. And when you even have members of 4chan telling others off for pirating your titles because of the lack of DRM and DLC methods, it's heartening.
Some older arcade games come with "suicide batteries" in the arcade hardware; when these batteries die, the game ceases to function properly in some way or another; in some cases, you'll just get garbled graphics or no sound; other times, the game will completely cease to be playable.
Nintendo's DRM is simply tying games to your console, is not inconvenient as long as your system is functioning, but if your system is not working you have no choice but to send to their customer service for them to transfer to a new system which is not very convenient, and if your system is lost or stolen you simply lost all your digital games for good