| 摘要 |
PROBLEM TO BE SOLVED: To easily supply an ID and a key of cryptograph to an electronic circulation system using a ROM disk by providing a write-once region where a bar code is overlapped to a pit part and individually storing an ID that differs for each disk, a key of cryptograph for communication as needed, and a decode key for a decode key cryptograph at the write-once region in manufacturing. SOLUTION: A first cryptograph that is obtained by encoding a content 777 with a cryptograph encoder 803 using a first key of cryptograph 802 is modulated by a PE-RZ modulator 917 such as a mastering device, and the modulation signal is recorded on a first recording region 919 of a stamper 800 as irregular pits. A completed disk 809 is obtained by the stamper 800. Then, BCA (write-once) trimming is made to a second recording region 920 of the completed disk 809 by modulating a disk ID, a decode key 922 of the first cryptograph, or a second cryptograph key 923 for Internet communication by a trimming device 807, thus manufacturing a disk 801 with BCA. |
