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DVD Copy Protection Types

Region Code

DVD video discs may be encoded with a region code restricting the area of the world in which they can be played. Discs without region coding are called all region or region 0 discs.

The commercial DVD player specification requires that a player to be sold in a given place not play discs encoded for a different region (region 0 discs are not restricted). The purpose of this is to allow motion picture studios to control aspects of a release, including content, release date, and, especially, price, according to the region. Many DVD players are or can be modified to be region-free, allowing playback of all discs.

Region code
Informal term meaning "worldwide". Region 0 is not an official setting; discs that bear the region 0 symbol either have no flag set or have region 1-6 flags set.
Canada, United States; U.S. territories; Bermuda
Southeast Asia; South Korea; Taiwan; Hong Kong
Australia; Oceania; Central and South America; Caribbean; Mexico
China, Hong Kong
Reserved for future use (found in use on protected screener copies of MPAA-related DVDs and "media copies" of pre-releases in Asia)
International venues such as aircraft, cruise ships, etc.
Region ALL discs have all 8 flags set, allowing the disc to be played in any locale on any player.

Region Code Enhanced (RCE)

Region Code Enhanced, also known as just "RCE" or "REA", this was a retroactive attempt to prevent the playing of one region's discs in another region, even if the disc was played in a region free player. The scheme was deployed on only a handful of discs. The disc contained the main programme material region coded as region 1. But it also contained a short video loop of a map of the world showing the regions, which was coded as region 2, 3, 4, 5, and 6. The idea was that when the disc was played in a non-region 1 player, the player would default to playing the material for its native region. This played the map, which was impossible to escape from, as the user controls were disabled.


As of 2007, many "multi-region" DVD players defeat regional lockout and RCE by automatically identifying and matching a disc's region code and/or allowing the user to manually select a particular region. Some manufacturers of DVD players now freely supply information on how to disable regional lockout, and on some recent models, it appears to be disabled by default. Programs such as DVD Shrink are also capable of removing RCE protection, provided the operator knows what the region of the disk actually is. If the region is specified correctly, the copy will play in any region.


Analog Protection System (APS)

The Analog Protection System (APS), also known as Copyguard, is a DVD copy prevention system originally developed by Macrovision. Video tapes copied from DVDs encoded with APS become garbled and unwatchable. The process works by adding pulses to analog video signals to negatively impact the AGC circuit of a recording device. In digital devices changes to the analog video signal are created by a chip that converts the digital video to analog within the device. In DVD players trigger bits are created during DVD authoring to inform the APS that it should be applied to DVD players analog outputs or analog video outputs on a PC while playing back a protected DVD-Video disc. In set top boxes trigger bits are incorporated into Conditional Access Entitlement Control Messages (ECM) in the stream delivered to the STB. In VHS alterations to the analog video signal are added in a Macrovision-provided "processor box" used by duplicators.

APS can be also signaled digitally, in the CGMS-A bit field sent in the vertical blanking interval.


Content Scramble System (CSS)

Content Scramble System (CSS) is a Digital Rights Management (DRM) scheme used on almost all commercially produced DVD-Video discs. It utilizes a relatively weak, proprietary 40-bit stream cipher algorithm. The system was introduced around 1996 and has subsequently been compromised.

The CSS key sets are licensed by the DVD Copy Control Association to manufacturers who incorporate them into products such as DVD movie releases, drives & players. Most DVD players are equipped with a CSS Decryption module. CSS key is a collective term for authentication key, disc keys, player keys, title keys, secured disk key set, and/or encrypted title keys.

Some of the keys are stored on the lead-in area of the disk, which is generally only read by compliant drives. Keys can be passed from a DVD drive to a descrambler over a PC bus using a secure handshake protocol.

The purpose of CSS is twofold. First and foremost, it prevents byte-for-byte copies of an MPEG stream from being playable since such copies will not include the keys that are hidden on the lead-in area of the protected DVD disk. Second, it provides a reason for manufacturers to make compliant devices, since CSS scrambled disks will not play on noncompliant devices. Anyone wishing to build compliant devices must obtain a license, which contains the requirement that the rest of the copy-protection system be implemented.

In October 1999, Jon Lech Johansen and two people who remained anonymous reverse engineered the algorithm and DeCSS was released. The CSS algorithm was soon revealed to be easily susceptible to a brute force attack, apart from being an example of the trusted client problem. The weakness of the protection is primarily due to US government crypto-export regulations, which, at the time, forbade the export of cryptosystems employing keys in excess of 40 bits - a key length that had already been proven to be wholly inadequate in the face of increasing processing power by the time DVD was released (see DES). In addition, structural flaws in the algorithm reduced the effective key length to only around 16 bits, which could be brute-forced by a 450 MHz processor in less than a minute. As a 450 MHz processor was the stated minimum necessary to decompress a DVD-compliant MPEG-2 videostream in realtime, it effectively meant that any computer that could play a DVD could also crack one.

The CSS algorithm has been superseded by the Cryptomeria cipher in newer DRM schemes such as CPRM/CPPM, or by AES in the AACS copy-protection scheme used by HD DVD.


User Operation Prohibition (UOP)

The user operation prohibition (abbreviated UOP) is a form of digital rights management used on video DVD discs. Most DVD players prohibit the viewer from performing a large majority of actions during sections of a DVD that are protected or restricted by this feature, and will display the no symbol or a message to that effect if any of these actions are attempted. It was intended for copyright notices and the ubiquitous (at least in the United States) FBI warning. Some publishers run "protected" (i.e., "unskippable") commercials on their DVDs, which is widely seen by consumers as an abuse of the feature.

Some DVD players ignore the UOP flag, allowing the user full control over DVD playback. Virtually all players that are not special-purpose DVD player hardware (for example, a player program running on a general purpose computer) ignore the flag. There are also modchips available for some standard DVD players for the same purpose, although modifying a device may be illegal in some countries. The UOP flag can be removed in DVD ripper software such as: DVD Decrypter, DVD Shrink, AnyDVD, MacTheRipper and K9Copy.

Nevertheless, removing UOP does not always provide navigation function in the restricted parts of the DVD. This is because those parts are sometimes lacking the navigation commands which allow skipping to the menu or other parts of the DVD. This has become more common in recent titles, in order to circumvent the UOP disabling that many applications or DVD players offer.

UOPs are also used for usability purposes, especially in interactive DVD content. The Next Cell, Previous Cell, and Resume features are often disabled during menus, for instance, to avoid confusing or unintended jumps between content items. DVD Games like "Scene It?" are another example of complex DVD programming in which UOPs are said to ensure a more enjoyable user experience.


Sony ARccOS Protection

ARccOS is a copy-protection system developed by Sony used on some DVDs. Designed as an additional layer to be used in conjunction with Content Scramble System (CSS), the system deliberately creates corrupted sectors on the DVD, which cause copying software to produce errors. Allegedly, "Normal" DVD players do not read these sectors since they follow a set of instructions encoded on the disc telling them to skip them. However, many users with "normal" DVD players still report unplayable discs, and in some cases total lock-up of their players. Less sophisticated DVD copying programs do not follow these instructions and instead try to read every sector on the disk sequentially, including the bad ones.

RipIt for the Mac, Slysoft's AnyDVD, Fengtao's DVDFab Decrypter, RipIt4Me + DVD Decrypter, FixVTS, DVD43, MacTheRipper, along with VLC media player, GNU ddrescue, dd_rescue and MPlayer/MEncoder (for Linux) are usually able to overcome ARccOS.

ARccOS had reportedly been discontinued by Sony in February 2006. However, several high-profile releases since then have used it, including the region 1 DVDs for Hostel, Underworld: Evolution, Running With Scissors, and Casino Royale. Many DVDs by Disney, Touchstone Pictures, and The Weinstein Company also use ARccOS including Pirates of the Caribbean: Dead Man's Chest, Cars, Flightplan, The U.S. vs. John Lennon, Lucky Number Slevin, and Ratatouille. Hairspray appears to also be encumbered with ARccOS. Many DVD rental companies are now warning users that the Sony DVDs in question may not play on their machines.

Despite being promoted as "fully compatible with available DVD players and drives," movies with ARccOS cannot be played on some DVD players: Sony DVPCX995, Toshiba SD4700, Harman Kardon DVD101, Microsoft Xbox and others. Sony has announced a future firmware update for their players to fix this incompatibility issue. One revision of the ARccOS scheme used by Sony was incompatible with a higher number of players than average. Sony has offered to replace those discs for owners having problems; the replacement discs will have a newer version of ARccOS coding on them, which Sony claims is more compatible.


Analog CPS (Macrovision)









Content Protection for Prerecorded Media (CPPM)



Content Protection for Recordable Media (CPRM)



Digital Copy Protection System (DCPS)






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