Method for determining an unauthorized copy of an optical disc

Details Method for determining an unauthorized copy of an optical disc Method for determining an unauthorized copy of an optical disc

1998-10-01

2000-08-15

Dinh, Tan

Dynamic information storage or retrieval

Information location or remote operator actuated control

Selective addressing of storage medium

G11B 1722

Patent

active

061046795

ABSTRACT:
A method of authenticating a Compact Disc, to distinguish an original Compact Disc from an unauthorized copy thereof. One or more invalid symbols are written into the subcode of the original Compact Disc, such one affecting the Q-channel, by using special equipment. The Q-channel normally contains only track location information whose format and content are precisely defined by the applicable standards, and thus ordinary consumer Compact Disc recording equipment does not receive external Q-channel input, but rather generates Q-channel data internally when recording. Therefore, invalid symbols affecting the Q-channel of an original Compact Disc cannot be copied by ordinary consumer Compact Disc recording equipment. Consequently, the presence of data in the Q-channel of a Compact Disc serves to distinguish an original Compact Disc from an unauthorized copy thereof. Invalid symbols include both symbols with incorrect values as well as bistable symbols, which cannot be copied by most professional mastering equipment. The present invention discloses methods for reading the Q-channel to determine the presence or absence of predetermined invalid data.

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patent: 5875156 (1999-02-01), Ito et al.
patent: 5881038 (1999-03-01), Oshima et al.
patent: 5930209 (1999-07-01), Spitzenberger et al.

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