Copy protection hole in Blu-ray and HD DVD movies
The Blu-ray Disc and HD DVD are new data carriers for high-resolution motion pictures. For fear of piracy, Hollywood had the developers install a cornucopia of copy prevention mechanisms on them. For instance, the film data on the disks are protected by means of the Advanced Access Content System (AACS). Digital output only reaches the monitor via connections encrypted by means of High Bandwidth Digital Content Protection (HDCP). This copy protection chain is designed to ensure that no unencrypted data can be grabbed.
But this security chain has a giant hole. Computer magazine c't has discovered that the first software players running on Windows XP allow screenshots of the movies to be created in full resolution. To do so, you only need to press the Print key on your keyboard while the movie is running. Such a screenshot function could then be automated to produce copies of HD movies both from Blu-ray Discs and from HD DVDs picture by picture. As c't calculated, the performance of current PC systems is sufficient for a clean recording using this procedure. Once a pirate has all of the individual pictures, they can be put together to create a complete movie and mixed with the audio track that is grabbed separately.
This copy protection hole affects both Sony's first Blu-ray PC Vaio VGC-RC 204 and Toshiba's first HD DVD notebook Qosmio G30. Both of them use special OEM versions of Intervideo's WinDVD player software.
When asked to comment, Toshiba confirmed the security hole found by c't, which affects the computers already sold, and announced updates for the player software and graphics card driver. These new software versions should disable the screenshot function.
According to Toshiba, however, the original WinDVD version does not violate the security stipulations in the AACS LA. Toshiba therefore does not expect the first WinDVD version to be blocked by an update of the AACS key. By switching the keys, which would be necessary for new HD DVD movies, the AACS LA could force users to update their software, thus closing the copy protection hole.
The next edition of c't, which goes on sale on Monday, July 10, describes this security hole and its effects in greater detail:
- Bilderklau durchs Fenster, Kopierschutzlücke für Blu-ray- und HD-DVD-Filme unter Windows XP, (Stealing pictures through Windows: copy protection hole for Blu-ray and HD DVD movies on Windows XP) c't15/06, p.60