Background
Hexadecimal is a base-16 numeral system used in the fields of computer programming and mathematics. The key is an ordinary number most widely known by its hexadecimal representation; in decimal notation, it is 13,256,278,887,989,457,651,018,865,901,401,704,640.
Because the encryption key may be used as part of circumvention technology forbidden by the DMCA, its possession and distribution has been viewed as illegal by the AACS, as well as by some legal professionals. Since it is a 128-bit numerical value, it was dubbed an illegal number. Opponents to the expansion of the scope of copyright criticize the idea of making a particular number illegal.
Commercial HD DVDs and Blu-ray Discs integrate copy protection technology specified by the AACS LA. There are several interlocking encryption mechanisms, such that cracking one part of the system does not necessarily crack other parts. Therefore, the "09 F9" key is only one of many parts that are needed to play a disc on an unlicensed player.
The AACS system can be used to revoke a key of a specific playback device, after it is known to have been compromised, as it has for WinDVD. The compromised players can still be used to view old discs, but not newer releases without encryption keys for the compromised players. If other players are then cracked, further revocation would lead to legitimate users of compromised players being forced to upgrade or replace their player software or firmware in order to view new discs. Each playback device comes with a binary tree of secret device and processing keys. The processing key in this tree, a requirement to play the AACS encrypted discs, is selected based on the device key and the information on the disc to be played. As such, a processing key such as the "09 F9" key is not revoked, but newly produced discs cause the playback devices to select a different valid processing key to decrypt the discs.
Read more about this topic: AACS Encryption Key Controversy
Famous quotes containing the word background:
“In the true sense one’s native land, with its background of tradition, early impressions, reminiscences and other things dear to one, is not enough to make sensitive human beings feel at home.”
—Emma Goldman (1869–1940)
“Silence is the universal refuge, the sequel to all dull discourses and all foolish acts, a balm to our every chagrin, as welcome after satiety as after disappointment; that background which the painter may not daub, be he master or bungler, and which, however awkward a figure we may have made in the foreground, remains ever our inviolable asylum, where no indignity can assail, no personality can disturb us.”
—Henry David Thoreau (1817–1862)
“I had many problems in my conduct of the office being contrasted with President Kennedy’s conduct in the office, with my manner of dealing with things and his manner, with my accent and his accent, with my background and his background. He was a great public hero, and anything I did that someone didn’t approve of, they would always feel that President Kennedy wouldn’t have done that.”
—Lyndon Baines Johnson (1908–1973)