Key2Audio
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- The correct title of this article is key2audio. The initial letter is shown capitalized due to technical restrictions.
key2audio is a copy protection system for Audio CDs, developed by Sony DADC. A hidden signature applied to the disc during glass master manufacturing prevents playback on PC/MAC and thereby prevents copying or track ripping.
Currently there are two major versions of the key2Audio protection: the original key2Audio, and key2AudioXS.
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[edit] key2Audio
key2audio products are mostly compatible because the audio part fully complies with the Red Book standard - not a single bit is changed in the audio data stream - however the CD by itself is not Red Book compliant any more and must not have a "Compact Disc" label.
This leads to problems on some CD players. Since optical computer CD/DVD drives are also capable of reading Red Book audio CDs, a lot of player manufacturers use these CD/DVD ROM drives instead of specialized Audio CD / Video DVD only drives in order to reduce costs.
DVD players and car stereo systems seem to have most problems with incompatibilities of key2Audio protected CDs.
A protected CD still achieves a maximum recording time of 77 minutes and supports full ISRC, UPC and CD-Text capabilities.
Early versions of this copy protection were famous for being easily circumvented with a marker pen, by drawing a tangential line on the rim of the visible edge of audio data.[1]
[edit] Technical background
It seems that key2Audio protected disc TOC contains three sessions written on the disc. Two of them contain small data tracks, the third one contains a data track and the audio tracks, and is not closed. The regular CD players pick the audio tracks outright, while the computer CD and DVD players get confused by the corrupted TOC information. CD players and drives that do not support multisession discs are immune against this confusion.
It can be worked around by eg. CloneCD or Exact Audio Copy.
[edit] key2AudioXS
key2audioXS™ combines user-friendly PC playback and a clone-proof Multimedia session for CD-Extra and Web Links.
The new version of this protection grants the listener the right to play the CD on a PC, and allow controlled burning the audio to CD. This solution allows consumers a limited amount of private copies. The record labels can individually define the burn count. These copies are then also fully protected and offer the same efficiency and compatibility as the original disc.
The audio sessions are being encoded to Windows Media Audio DRM-protected files, so that some portable devices are supported and online distribution prevented.
Furthermore, with key2audioXS™ the user can now pick and send audio tracks via email. With a usability period defined by the record label, users can share music, facilitating promotion activities for labels. Additionally, some discs feature "n-CD", which lets the user access bonus features, videos, ringtones, lotteries and similar added goodies. The original n-CD is a unique key reserved for just their owners.
For this purpose, the user interface for key2Audio on PC allows for navigation and includes a copying and burning tool, as well as additional content such as bonus pictures and lyrics.
The audio part can hold up to 75 minutes.
