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Content Scrambling System
The Content Scramble System (CSS) is a digital rights management (DRM) and encryption system employed on many commercially produced DVD-Video discs. CSS utilizes a proprietary 40-bit stream cipher algorithm. The system was introduced around 1996 and was first compromised in 1999. CSS is one of several complementary systems designed to restrict DVD-Video access. It has been superseded by newer DRM schemes such as Content Protection for Recordable Media (CPRM), or by Advanced Encryption Standard (AES) in the Advanced Access Content System (AACS) DRM scheme used by HD DVD and Blu-ray Disc, which have 56-bit and 128-bit key sizes, respectively, providing a much higher level of security than the less secure 40-bit key size of CSS. Preliminary note The content scramble system (CSS) is a collection of proprietary protection mechanisms for DVD-Video discs. CSS attempts to restrict access to the content only for licensed applications. According to the DVD Copy Control Associ ...
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DVD Forum
The DVD Forum is an international organization composed of hardware, software, media and production companies that use and develop the DVD and formerly HD DVD formats. It was initially known as the DVD Consortium when it was founded in 1995. History and mission The DVD Forum was created to facilitate the exchange of information and ideas about the DVD format, another evolution of the LaserDisc format, and to enable it to grow through technical improvement and innovation. The organization hopes to promote worldwide acceptance of DVD for entertainment, consumer electronics and information technology applications. Membership in the DVD Forum is open to any company or organization involved in DVD research, development, or manufacturing; software firms and other DVD users interested in developing the format are also encouraged to join. Forum members can support other formats in addition to DVD. The DVD Forum is responsible for the official DVD format specification. The group handle ...
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Blu-ray Disc
The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of storing several hours of high-definition video (HDTV 720p and 1080p). The main application of Blu-ray is as a medium for video material such as feature films and for the physical distribution of video games for the PlayStation 3, PlayStation 4, PlayStation 5, Xbox One, and Xbox Series X. The name "Blu-ray" refers to the blue laser (which is actually a violet laser) used to read the disc, which allows information to be stored at a greater density than is possible with the longer-wavelength red laser used for DVDs. The polycarbonate disc is in diameter and thick, the same size as DVDs and CDs. Conventional or pre-BD-XL Blu-ray Discs contain 25  GB per layer, with dual-layer discs (50 GB) being the industry standard for featu ...
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Export Of Cryptography In The United States
The export of cryptography from the United States to other countries has experienced various levels of restrictions over time. World War II illustrated that code-breaking and cryptography can play an integral part in national security and the ability to prosecute war. Changes in technology and the preservation of free speech have been competing factors in the regulation and constraint of cryptographic technologies for export. History Cold War era In the early days of the Cold War, the U.S. and its allies developed an elaborate series of export control regulations designed to prevent a wide range of Western technology from falling into the hands of others, particularly the Eastern bloc. All export of technology classed as 'critical' required a license. CoCom was organized to coordinate Western export controls. Two types of technology were protected: technology associated only with weapons of war ("munitions") and dual use technology, which also had commercial applications. In ...
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Linear-feedback Shift Register
In computing, a linear-feedback shift register (LFSR) is a shift register whose input bit is a linear function of its previous state. The most commonly used linear function of single bits is exclusive-or (XOR). Thus, an LFSR is most often a shift register whose input bit is driven by the XOR of some bits of the overall shift register value. The initial value of the LFSR is called the seed, and because the operation of the register is deterministic, the stream of values produced by the register is completely determined by its current (or previous) state. Likewise, because the register has a finite number of possible states, it must eventually enter a repeating cycle. However, an LFSR with a well-chosen feedback function can produce a sequence of bits that appears random and has a very long cycle. Applications of LFSRs include generating pseudo-random numbers, pseudo-noise sequences, fast digital counters, and whitening sequences. Both hardware and software implementation ...
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Keystream
In cryptography, a keystream is a stream of random or pseudorandom characters that are combined with a plaintext message to produce an encrypted message (the ciphertext). The "characters" in the keystream can be bits, bytes, numbers or actual characters like A-Z depending on the usage case. Usually each character in the keystream is either added, subtracted or XORed with a character in the plaintext to produce the ciphertext, using modular arithmetic. Keystreams are used in the one-time pad cipher and in most stream ciphers. Block ciphers can also be used to produce keystreams. For instance, CTR mode is a block mode that makes a block cipher produce a keystream and thus turns the block cipher into a stream cipher. Example In this simple example we use the English alphabet of 26 characters from a-z. Thus we can not encrypt numbers, commas, spaces and other symbols. The random numbers in the keystream then have to be at least between 0 and 25. To encrypt we add the keystr ...
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Regional Playback Control
RPC-1 and RPC-2 are designations applied to firmware for DVD drive In computing, an optical disc drive is a disc drive that uses laser light or electromagnetic waves within or near the visible light spectrum as part of the process of reading or writing data to or from optical discs. Some drives can only r ...s. Older DVD drives use RPC-1 firmware, which allows DVDs from any region to play. Newer drives use RPC-2 firmware, which enforces DVD region coding at the hardware level. See DVD region code#Computer DVD drives for further information. Some RPC-2 drives can be converted to RPC-1 with the same features as before by using alternative firmware on the drive, or on some drives by setting a secret flag in the drive's EEPROM. Computer storage media DVD {{compu-hardware-stub ...
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DVD Region Code
DVD region codes are a digital rights management technique introduced in 1997. It is designed to allow rights holders to control the international distribution of a DVD release, including its content, release date, and price, all according to the appropriate region. This is achieved by way of region-locked DVD players, which will play back only DVDs encoded to their region (plus those without any region code). The American DVD Copy Control Association also requires that DVD player manufacturers incorporate the regional-playback control (RPC) system. However, region-free DVD players, which ignore region coding, are also commercially available, and many DVD players can be modified to be region-free, allowing playback of all discs. DVDs may use one code, multiple codes (multi-region), or all codes (region free). Region codes and countries Any combination of regions can be applied to a single disc. For example, a DVD designated Region 2/4 is suitable for playback in Europe, L ...
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MPEG Program Stream
Program stream (PS or MPEG-PS) is a container format for multiplexing digital audio, video and more. The PS format is specified in MPEG-1 Part 1 (ISO/IEC 11172-1) and MPEG-2 Part 1, Systems (ISO/IEC standard 13818-1/ITU-T H.222.0). The MPEG-2 Program Stream is analogous and similar to ISO/IEC 11172 Systems layer and it is forward compatible.ISO (2000-12-01ISO/IEC 13818-1 : 2000, Second editionPage X, Retrieved on 2009-07-25 Program streams are used on DVD-Video discs and HD DVD video discs, but with some restrictions and extensions.DVD - MPeg differences
Retrieved on 2009-07-24
The filename extensions are VOB and EVO respectively.


Coding structure
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SCSI Multimedia Commands
SCSI Multimedia Commands (MMC) defines a SCSI/ ATAPI based command set for accessing and controlling devices of type 05h. Such devices read or write optical media: CD, DVD, BD. T10 subcommittee is responsible for developing MMC as well as other SCSI command set standards. It was approved in December 1997 by ANSI.http://www.13thmonkey.org/documentation/SCSI/x3_304_1997.pdf (MMC-3) See also * Mount Rainier (MRW) *Layer Jump Recording (LJR) *Optical disc recording modes *Small Form Factor committee The Small Form Factor Committee (SFF) is an ''ad hoc'' electronics industry group formed to quickly develop interoperability specifications (as a complement to the traditional standards process). The SFF Committee was formed in 1990 to define the ... (SFF) References SCSI {{tech-stub ...
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Reverse Engineering
Reverse engineering (also known as backwards engineering or back engineering) is a process or method through which one attempts to understand through deductive reasoning how a previously made device, process, system, or piece of software accomplishes a task with very little (if any) insight into exactly how it does so. It is essentially the process of opening up or dissecting a system to see how it works, in order to duplicate or enhance it. Depending on the system under consideration and the technologies employed, the knowledge gained during reverse engineering can help with repurposing obsolete objects, doing security analysis, or learning how something works. Although the process is specific to the object on which it is being performed, all reverse engineering processes consist of three basic steps: Information extraction, Modeling, and Review. Information extraction refers to the practice of gathering all relevant information for performing the operation. Modeling refers to th ...
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Libdvdcss
libdvdcss (or libdvdcss2 in some repositories) is a free and open-source software library for accessing and unscrambling DVDs encrypted with the Content Scramble System (CSS). libdvdcss is part of the VideoLAN project and is used by VLC media player and other DVD player software packages, such as Ogle, xine-based players, and MPlayer. Comparison with DeCSS libdvdcss is not to be confused with DeCSS. Whereas DeCSS uses a cracked DVD player key to perform authentication, libdvdcss uses a generated list of possible player keys. If none of them work (for instance, when the DVD drive enforces region coding), libdvdcss brute-forces the key, ignoring the DVD's region code (if any). The legal status of libdvdcss is controversial but there has been—unlike DeCSS—no known legal challenge to it as of June 2022. Distribution Many Linux distributions do not contain libdvdcss (for example, Debian, Ubuntu, Fedora and openSUSE) due to fears of running afoul of DMCA-style laws, but they ...
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Open-source Software
Open-source software (OSS) is computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. Open-source software may be developed in a collaborative public manner. Open-source software is a prominent example of open collaboration, meaning any capable user is able to participate online in development, making the number of possible contributors indefinite. The ability to examine the code facilitates public trust in the software. Open-source software development can bring in diverse perspectives beyond those of a single company. A 2008 report by the Standish Group stated that adoption of open-source software models has resulted in savings of about $60 billion per year for consumers. Open source code can be used for studying and allows capable end users to adapt software to their personal needs in a similar way user scripts a ...
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