| 摘要 |
PURPOSE:To prevent recorded software and music information from being copied without raising cost for an optical disk for supplying the software and music information. CONSTITUTION:Main data obtained by ciphering its original data based on key information is recorded in a data recording area 3 of the optical disk 2, and the key information is recorded in a nondata recording area 4. Then, the key information is read out by a key information reading means 9 of a reproducing device, and a deciphering method is settled by a deciphering means 10 based on this key information, and then the main data is deciphered by this settled deciphering method to reproduce the original data. |
