The Advanced Access Content System (AACS) is a standard for content distribution and digital rights management, intended to restrict access to and copying of the next generation of optical discs and DVDs. The specification was publicly released in April 2005 and the standard has been adopted as the access restriction scheme for HD DVD and Blu-ray Disc (BD). It is developed by AACS Licensing Administrator, LLC (AACS LA), a consortium that includes Disney, Intel, Microsoft, Matsushita (Panasonic), Warner Brothers, IBM, Toshiba and Sony. Standardization, in the context related to technologies and industries, is the process of establishing a technical standard among competing entities in a market, where this will bring benefits without hurting competition. ... Content delivery describes the delivery of digital media content such as digital audio or digital video over a delivery medium such as broadcasting or the Internet. ... Digital Rights Management (generally abbreviated to DRM) is an umbrella term that refers to any of several technologies used by publishers or copyright owners to control access to and usage of digital data or hardware, and to restrictions associated with a specific instance of a digital work or device. ... Copying is the duplication of information, or an artifact, based only on an instance of that information or artifact, and not using the process that originally generated it. ... Generation (From the Greek γιγνμαι), also known as procreation, is the act of producing offspring. ... DVD (also known as Digital Versatile Disc or, incorrectly, Digital Video Disc) is an optical disc storage media format that can be used for data storage, including movies with high video and sound quality. ... HD-DVD disc HD DVD (for High Density Digital Versatile Disc) is a digital optical media format which is being developed as one standard for high-definition DVD. HD DVD is similar to the competing Blu-ray Disc, which also uses the same CD sized (120 mm diameter) optical data... A Blu-ray Disc (also called BD) is a high-density optical disc format for the storage of digital media, including high-definition video. ... A consortium is an association of two or more individuals, companies, organisations or governments (or any combination of these entities) with the objective of participating in a common activity or pooling their resources for achieving a common goal. ... The Walt Disney Company (NYSE: DIS) is one of the largest media and entertainment corporations in the world. ... Intel Corporation (NASDAQ: INTC, SEHK: 4335), founded in 1968 as Integrated Electronics Corporation, is an American multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ... Logo for the Panasonic brand Matsushita Electric Industrial Co. ... Warner Bros. ... International Business Machines Corporation (known as IBM or Big Blue; NYSE: IBM) is a multinational computer technology and consulting corporation headquartered in Armonk, New York, USA. The company is one of the few information technology companies with a continuous history dating back to the 19th century. ... Toshiba Corporations headquarters (Center) in Hamamatsucho, Tokyo Toshiba Corporation sales by division for year ending March, 31 2005 Toshiba Corporation ) (TYO: 6502 ) is a multinational high technology electrical and electronics manufacturing firm, headquartered in Tokyo, Japan. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $68. ...

Since appearing in devices in 2006, several successful attacks have been made on the format. The first known attack relied on the trusted client problem. In addition, decryption keys have been extracted from a weakly protected player (WinDVD). In computing, a trusted client is a device or program controlled by the user of a service, but with restrictions designed to prevent its use in ways not authorised by the provider of the service. ... The WinDVD interface WinDVD is a commercial DVD player for Microsoft Windows, created by InterVideo. ...

System overview

Encryption

AACS uses cryptography to control the use of digital media. It encrypts content under one or more title keys using the Advanced Encryption Standard (AES). Title keys are derived from a combination of a media key and several elements, including the volume ID of the media (e.g., a physical serial number embedded on a DVD), and a cryptographic hash of the title's usage rules. The German Lorenz cipher machine, used in World War II for encryption of very high-level general staff messages Cryptography (or cryptology; derived from Greek κρυπτός kryptós hidden, and the verb γράφω gráfo write) is the study of message secrecy. ... In cryptography, the Advanced Encryption Standard (AES), also known as Rijndael, is a block cipher adopted as an encryption standard by the U.S. government. ... In cryptography, a cryptographic hash function is a hash function with certain additional security properties to make it suitable for use as a primitive in various information security applications, such as authentication and message integrity. ...

The principal difference between an AACS key and earlier content scramble systems such as CSS is in the means by which title-specific decryption keys are distributed. The AACS encryption key controversy arose in April 2007 when the Motion Picture Association of America and the Advanced Access Content System Licensing Administrator, LLC (AACS LA) began issuing Digital Millennium Copyright Act (DMCA) violation notices [1] to websites publishing a 16-byte number, represented in hexadecimal as 09 F9... Content Scramble System (CSS) is a Digital Rights Management (DRM) scheme used on some DVDs. ...

Under CSS, all players of a given model are provisioned with the same, shared decryption key. Content is encrypted under the title-specific key, which is itself encrypted under each model's key. Thus each disc contains a collection of several hundred encrypted keys, one AACS key for each licensed player model. Content Scramble System (CSS) is a Digital Rights Management (DRM) scheme used on some DVDs. ... The AACS encryption key controversy arose in April 2007 when the Motion Picture Association of America and the Advanced Access Content System Licensing Administrator, LLC (AACS LA) began issuing Digital Millennium Copyright Act (DMCA) violation notices [1] to websites publishing a 16-byte number, represented in hexadecimal as 09 F9...

In principle, this approach allows licensors to "revoke" a given player model (prevent it from playing back future content) by omitting to encrypt future title keys with the player model's key. In practice, however, revoking all players of a particular model is costly, as it causes many users to lose playback capability. Furthermore, the inclusion of a shared key across many players makes key compromise significantly more likely, as was demonstrated by a number of compromises in the mid-1990s.

The approach of AACS provisions each individual player with a unique set of decryption keys which are used in a broadcast encryption scheme. This approach allows licensors to "revoke" individual players, or more specifically, the decryption keys associated with the player. Thus, if a given player's keys are compromised and published, the AACS licensing authority can simply revoke an AACS key in future content, making the keys/player useless for decrypting new titles. Broadcast encryption is the cryptographic problem of encrypting broadcasted content (e. ... The AACS encryption key controversy arose in April 2007 when the Motion Picture Association of America and the Advanced Access Content System Licensing Administrator, LLC (AACS LA) began issuing Digital Millennium Copyright Act (DMCA) violation notices [1] to websites publishing a 16-byte number, represented in hexadecimal as 09 F9...

If an attacker tries to keep a compromised key secret (by only publishing decrypted title keys), it can still be tracked down. The AACS standard allows different versions of short sections of a movie to be encrypted with different keys. A certain player will only be able to decrypt one version of each section. By embedding a digital watermark in the different versions and analyzing what sections of the movie the attacker publishes, the compromised keys can eventually be identified and revoked (this feature is called Sequence keys in the AACS specifications).^{[1] [2]} An image with visible digital watermarking. ...

Volume IDs

It has been suggested that Volume Identifier be merged into this article or section. (Discuss)

Volume IDs are unique identifiers or serial numbers that are stored on pre-recorded discs with special hardware. They cannot be duplicated on consumers' recordable media. This prevents simple bit-by-bit copies, since the Volume ID is required (though not sufficient) for decoding content. Image File history File links Please see the file description page for further information. ... It has been suggested that this article or section be merged into Advanced Access Content System#Volume_IDs . ...

To read the Volume ID, a cryptographic certificate signed by the AACS LA is required. However, hackers claim to have circumvented that particular protection by modifying the firmware of a HD DVD reader.^{[3] [4]} A certificate is an official document affirming some fact. ...

Plugging the analog hole

Main article: Image Constraint Token

AACS-compliant players must follow guidelines pertaining to outputs over analog connections. This is set by a flag called the Image Constraint Token (ICT), which restricts the resolution for analog outputs to 960×540. Full 1920×1080 resolution is restricted to HDMI outputs with HDCP. The decision to set the flag to restrict output ("down-convert") is left to the content provider. Warner Pictures is a proponent of ICT, and it is expected that Paramount and Universal will implement down-conversion as well.^[5] As of March 2006, 5 of the 6 studios releasing HD DVD content have announced they will not use ICT/down-conversion for the time being.^[6] AACS guidelines require that any title that implements the ICT must clearly state so on the packaging. The analog hole is a fundamental, and inevitable vulnerability in copy prevention schemes for noninteractive digital content which is intended to be played back using analog means. ... Image Constraint Token, or ICT, is a flag that causes downsampling of high-definition content on Blu-ray and HD DVD to slightly-better-than-DVD quality video. ... High-bandwidth Digital Content Protection (HDCP) is a form of the controversial Digital Rights Management (DRM) developed by Intel Corporation to control digital audio and video content as it travels across Digital Visual Interface (DVI) or High-Definition Multimedia Interface (HDMI) connections. ...

Audio watermarking

It is possible to use Verance's audio watermarking technology^[7] in conjunction with AACS. Studios may insert an inaudible mark in the soundtracks of theatrical motion pictures. If an AACS-compliant player does not detect the inaudible mark, it means the disc is playing back a copy made from a theatrical print (probably from illegal camcording), and will cause the player to refuse to play the disc. The mark is made by varying the waveform of speech and music in a regular pattern to convey a digital code. These variations are too subtle to be heard by the human ear. Another variation of this system can be used to prevent the playback of discs created by using a camcorder and microphone on a home entertainment center playing a legitimate disc purchased by a consumer. This variation for home entertainment utilizes a watermark that differs from the cinema mark in that it is permitted in normal, signed ROM discs, but generally not permitted on recordable discs. An image with visible digital watermarking. ... Sign can denote any of the following: Within a writing system, a sign is a basic unit. ...

Managed Copy

AACS has specified protocols for optionally allowing consumers to make backup copies or move content to a portable player in a controlled way. This requires the device to obtain authorization by contacting a remote server on the Internet. This feature was standardized relatively late, so the first devices on the market did not have this capability.^[8] It is mandatory for content providers to give the consumer this flexibility in both the HD DVD and the Blu-ray standards (commonly called Mandatory Managed Copy). The Blu-ray standards adopted Mandatory Managed Copy later than HD DVD, after HP requested it.^[9] The Hewlett-Packard Company (NYSE: HPQ), commonly known as HP, is a very large, global company headquartered in Palo Alto, California, United States. ...

Open-source implementations

On December 26, 2006 a person using the alias "muslix64" published a working, open-sourced AACS decrypting utility named BackupHDDVD, looking at the publicly available AACS specifications. Given the correct keys, it can be used to decrypt AACS-encrypted content. Soon a corresponding BackupBluRay program was developed.^[10] December 26 is the 360th day of the year in the Gregorian calendar, 361st in leap years. ... For the Manfred Mann album, see 2006 (album). ... 09-f9-11-02-9d-74-e3-5b-d8-41-56-c5-63-56-88-c0 BackupHDDVD is a small open-source utility available in both command line and GUI-based versions which aids in the decryption of AACS copy-protected commercial HD DVD discs. ... It has been suggested that this article or section be merged into BackupHDDVD. (Discuss) BackupBluRay is a free, open source utility which aids in the decryption of AACS copy-protected content on Blu-ray discs, presumably for the purpose of backing up a film that a consumer has purchased. ...

Security of AACS

Concerns of experts

The proposal was voted one of the technologies most likely to fail by IEEE Spectrum magazine's readers in the January 2005 issue.^[11] Concerns about the approach include its similarity to past systems that failed, such as CSS, and the inability to preserve security against attacks that compromise large numbers of players. Jon Lech Johansen, who was part of the team that circumvented CSS, expected AACS to be cracked by winter 2006/2007.^[12] IEEE Spectrum is a magazine edited by the Institute of Electrical and Electronics Engineers. ... Jon Lech Johansen Jon Lech Johansen (born in Harstad November 18, 1983), also known as DVD-Jon, is a Norwegian (his father is Norwegian and mother is Polish) who is famous for his work on reverse engineering data formats. ...

In late 2006, security expert Peter Gutmann released "A Cost Analysis of Windows Vista Content Protection", a technical paper criticizing the implementation of AACS on Windows Vista.^[13] Peter Gutmann is a computer scientist in the Department of Computer Science at the University of Auckland, Auckland, New Zealand; he also received his Ph. ... Windows Vista is a line of graphical operating systems used on personal computers, including home and business desktops, notebook computers, Tablet PCs, and media centers. ...

Print Screen vulnerability

While great care has been taken with AACS to ensure that contents are encrypted right up to the display device, it was discovered in July 2006 that a perfect copy of any still frame from a film could be captured from certain Blu-ray and HD DVD software players made simply by utilizing the Print Screen function of the Windows operating system.^{[14] [15]} It was hypothesized that this approach could be automated to allow a perfect copy of an entire film to be made, in much the same way that DVD films were copied before the advent of DeCSS, but to date no such copy has been discovered. This exploit has been closed in subsequent software versions. For the Manfred Mann album, see 2006 (album). ... Blu-ray discs Blu-ray Disc is a next-generation optical disc format jointly developed by a group of leading consumer electronics and PC companies called the Blu_ray Disc Association (BDA), which succeeds the Blu_ray Disc Founders (BDF). ... HD-DVD disc HD DVD (for High Density Digital Versatile Disc) is a digital optical media format which is being developed as one standard for high-definition DVD. HD DVD is similar to the competing Blu-ray Disc, which also uses the same CD sized (120 mm diameter) optical data... A 102-key PC US English keyboard layout with the print screen key marked in red. ... DeCSS is a computer program capable of decrypting content on a DVD video disc encrypted using the Content-Scrambling System (CSS). ...

Such approaches do not constitute compromises of the AACS encryption itself, relying instead on an officially licensed software player to perform the decryption. As such, the output data will not be in the form of the compressed video from the disc, but rather decompressed video.

Memory-space snooping attacks

Both title keys and one of the keys used to decrypt them (known as Processing Keys in the AACS specifications) have been found by using debuggers to inspect the memory space of running HD-DVD and Blu-ray player programs.^{[16] [17] [18] [19]} Hackers also claim to have found Device Keys ^[20] (used to calculate the Processing Key) and a Host Private Key ^[21] (a key signed by the AACS LA used for hand-shaking between host and HD drive; required for reading the Volume ID). The first pirated HD movies were available soon afterwards.^[22] The processing key was widely published on the Internet after it was found and the AACS LA sent multiple DMCA takedown notices in the aim of censoring it.^[23] Some sites that rely on user-submitted content, like Digg and Wikipedia, tried to remove any mentions of the key.^{[24] [25]} The Digg administrators eventually gave up trying to censor submissions that contained the key.^[26] The Online Copyright Infringement Liability Limitation Act (OCILLA), a portion of the Digital Millennium Copyright Act known as DMCA 512 or the DMCA takedown provisions, is a 1998 United States federal law that provided a safe harbor to online service providers (OSPs, including internet service providers) that promptly take down... Digg is a community-based popularity website with an emphasis on technology and science articles, recently expanding to a broader range of categories such as politics and entertainment. ... Wikipedia - Wikipedia, the free encyclopedia /**/ @import /skins-1. ...

For more details on this topic, see AACS encryption key controversy.

Cyberlink, developers of PowerDVD stated that their software was not used as part of these exploits.^[27] The AACS encryption key controversy arose in April 2007 when the Motion Picture Association of America and the Advanced Access Content System License Authority (AACS LA) began issuing notices [1] to websites publishing a 16-byte hexadecimal number, 09 F9 . ... Founded in 1995, CyberLink Corp is a world leader and pioneer in bringing advanced digital video and audio software to the market. ... PowerDVD is a media player software product available from CyberLink. ...

On April 16, 2007, the AACS consortium announced that it had expired certain encryption keys used by PC-based applications. Patches were available for WinDVD and PowerDVD which used new and uncompromised encryption keys.^{[28] [29]} The compromised keys can still be used to decrypt old titles, but not newer releases as they will be encrypted with other, uncompromised keys. Legitimate users of the affected players are forced to upgrade or replace their player software in order to view new titles.

Updates to software players were released in April 2007, with new titles incorporating the updated keys etc. due on 22nd May 2007. However, by 16th May, software said to be capable of copying the updated disks was circulating the Internet, and reports started appearing that it was successfully copying titles encrypted with new keys that had been released early.

The use of encryption does not offer any true protection against memory snooping, since the software player must have the encryption key available somewhere in memory and there is no way to protect against a determined PC owner extracting the encryption key (if everything else fails the user could run the program in a virtual machine making it possible to freeze the program and inspect all memory addresses without the program knowing). In computer science, a virtual machine is software that creates a virtualized environment between the computer platform and its operating system, so that the end user can operate software on an abstract machine. ...

The only way to wholly prevent attacks like this would require changes to the PC platform (see Trusted Computing) or that the content distributors do not permit their content to be played on PCs at all (by not providing the companies making software players with the needed encryption keys). Trusted Computing Group, the creators of trusted computing Trusted Computing (commonly abbreviated TC) is a technology developed and promoted by the Trusted Computing Group (TCG). ...

Publishing of volume keys

On January 15, 2007 a website launched at HDKeys.com containing a database of HD DVD title keys. It also featured a modified copy of the BackupHDDVD software allowing for online key retrieval (the latter was later removed after a DMCA complaint). January 15 is the 15th day of the year in the Gregorian calendar. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... The Digital Millennium Copyright Act (DMCA) is a controversial United States copyright law which criminalizes production and dissemination of technology that can circumvent measures taken to protect copyright, not merely infringement of copyright itself, and heightens the penalties for copyright infringement on the Internet. ...

AnyDVD HD

SlySoft has released AnyDVD HD which allows users to watch HD DVD and Blu-ray movies on non-HDCP-compliant PC hardware. The movies can be decrypted on the fly directly from the disc, or can be copied to another medium. AnyDVD HD is also capable of automatically removing any unwanted logos and trailers. Slysoft has stated that AnyDVD HD uses several different mechanisms to disable the encryption, and is not dependent on the use of compromised encryption keys. They have also stated that AACS has even more flaws in its implementation than CSS; this renders it highly vulnerable,^[30] but they will release no details on their implementation. Users at Doom9 claim that the program makes use of the host certificate of PowerDVD version 6.5,^[31] but SlySoft has claimed that the program would be unaffected by the AACS revocation system.^[32] SlySoft Inc. ... AnyDVD is a Windows driver that decrypts and removes protection from DVDs on-the-fly. ... HDCP (High-bandwidth Digital Content Protection) is a specification developed by Intel Corporation to protect digital audio and video content as it travels across Digital Visual Interface (DVI) or High Definition Multimedia Interface (HDMI) connections. ... PowerDVD is a media player software product available from CyberLink. ...

References

2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 4 is the 124th day of the year in the Gregorian calendar (125th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 4 is the 124th day of the year in the Gregorian calendar (125th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 4 is the 124th day of the year in the Gregorian calendar (125th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 4 is the 124th day of the year in the Gregorian calendar (125th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... For the Manfred Mann album, see 2006 (album). ... February 5 is the 36th day of the year in the Gregorian calendar. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 3 is the 123rd day of the year in the Gregorian calendar (124th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 3 is the 123rd day of the year in the Gregorian calendar (124th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 4 is the 124th day of the year in the Gregorian calendar (125th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 4 is the 124th day of the year in the Gregorian calendar (125th in leap years). ... Peter Gutmann is a computer scientist in the Department of Computer Science at the University of Auckland, Auckland, New Zealand; he also received his Ph. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... January 28 is the 28th day of the year in the Gregorian calendar. ... Slashdot, often abbreviated as /., is a science, science fiction, and technology-related news website which features user-submitted and editor-evaluated current affairs news with a nerdy slant. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... January 2 is the second day of the year in the Gregorian calendar. ... The current BBC News logo BBC News and Current Affairs is a major arm of the BBC responsible for the corporations newsgathering and production of news programmes on BBC television, radio and online. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... January 22 is the 22nd day of the year in the Gregorian calendar. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... January 22 is the 22nd day of the year in the Gregorian calendar. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 4 is the 124th day of the year in the Gregorian calendar (125th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 4 is the 124th day of the year in the Gregorian calendar (125th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 3 is the 123rd day of the year in the Gregorian calendar (124th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... This article or section does not adequately cite its references or sources. ... The current BBC News logo BBC News and Current Affairs is a major arm of the BBC responsible for the corporations newsgathering and production of news programmes on BBC television, radio and online. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 3 is the 123rd day of the year in the Gregorian calendar (124th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... April 9 is the 99th day of the year in the Gregorian calendar (100th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... April 9 is the 99th day of the year in the Gregorian calendar (100th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... April 9 is the 99th day of the year in the Gregorian calendar (100th in leap years). ...

External links

• AACS homepage
• AACS specifications
• Understanding AACS, an introductory forum thread.
• ISAN homepage, ISAN as required in the Content ID defined in AACS Introduction and Common Cryptographic Elements rev 0.91