DVD Demystified

DVD on Computers
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disc key. Once a player retrieves and decrypts the disc key from its slot in
the key block, it can use the disc key to decrypt the title key stored in the
sector header of each encrypted sector. Each VTS on the disc uses a different
title key. The decrypted title key is used to decrypt the video or audio
contents of sectors that are encrypted with the CSS stream cipher.
CSS Licensing and Compliance CSS-compliant computers are
required to have the following:
■ A CSS-licensed DVD-ROM drive with authentication hardware
■ CSS-licensed decoding hardware/software, including an authenticator
and decryptor
■ CSS-licensed video components
■ Regional management support
■ Protection of digital output
■ Protection of analog video output (other than RGB)
■ Prevention against copying decrypted files
■ Rejection of “no copies allowed” material on a recordable disc (may be
provided by the drive or system)
Any computer industry segment involved in the production or integration
of hardware or software components that are affected by CSS may be
required to obtain a license and abide by its restrictions, as follows:
Operating System Makers A CSS license is not officially required, but the
operating system should protect decrypted data so that it cannot be copied
either as files or as data streams. For example, a video T filter must not be
allowed to split off a stream of decrypted video during playback. The OS
must also not enable complete bit-image copies of DVD-Video discs.
The OS must support the regional management for DVD-Video discs if
not handled elsewhere. The OS must provide for, or not interfere with, DPS
and APS information in the video output.
Application Developers A CSS license may be required if the application
directly manipulates DVD-Video files. The application is subject to the
same restrictions as an OS (refer to the preceding section).
Disc Manufacturers Companies that master and replicate encrypted discs
must have a CSS license in order to apply disc keys and encrypt sectors.