摘要 |
PURPOSE:To unnecessitate control of key information for deciphering ciphered data recorded in a CD-ROM disk. CONSTITUTION:When desired information is ciphered and recorded in the CD- ROM disk 1, key information required for decoding this ciphered information is recorded in a proper region 3 in the CD-ROM disk 1 with the ciphering information. When recorded contents of the CD-ROM disk 1 in which ciphering information is recorded by this recording system are reproduced, a desired key information is read out from the same CD-ROM disk 1 with ciphering information, and the ciphered information can be deciphered by only this read- out information. |