REPRODUCTION-ONLY OPTICAL DISK WITH DUPLICATION RESTRICTION FUNCTION, ITS DISTRIBUTING METHOD AND REPRODUCING APPARATUS COMPATIBLE WITH THE DISK

摘要

PROBLEM TO BE SOLVED: To provide a reproduction-only digital optical disk which has a duplication restriction function and which has encrypted digital data and to provide a reproducing apparatus compatible with the disk. SOLUTION: The reproduction-only digital optical disk with the duplication restriction function includes implementation of a digital literary work, a variable user data format for encoding the digital literary work after encryption by using a variable software algorithm, and a variable user data format encoded in the default format. Encrypted digital data are read with a digital optical disk playback apparatus which can accommodate to the user data format written in on the reproduction-only digital optical disk and which is compatible with the disk. The reproduction-only digital optical disc provides required user data format information on the disk in the default format which the reproducing apparatus compatible with the disk can access.