| 摘要 |
PROBLEM TO BE SOLVED: To make a third person impossible to obtain a key signal directly from the recording medium, by recording a scrambled signal, a cryptographic key signal produced by moreover ciphering a key signal generated based on random numbers and ciphered section control information for controlling a ciphered section of scramble and key signals. SOLUTION: AV data as an original data belonging to a copyright holder 1 is compressed and multiplexed in an authoring studio 2, and is ciphered in a disk cutting factory 2 by a key signal in relation to such a key signal under management by a key signal management agent 4, and then a disk is cut. Then, at the time of manufacturing a cutting data in the disk cutting factory 3, the data is scrambled by a key signal for encipherment. Particularly, an operating section is controlled so as to change the key signal depending only upon the inside with regard to time intervals. |
