| 摘要 |
PROBLEM TO BE SOLVED: To enable a viewer to view contents 'which are inhibited from being copied' only once at desired time and also copy and edit contents 'which can be copied once' only once after recording them on a medium, and to ensure the security of data at this time. SOLUTION: This decoding method which deciphers information, composed of successive unit blocks, which are ciphered by the unit blocks, is characterized by that the seed of a coding key for decoding a specific unit block is based upon one or more blocks other than the specified unit block or information generated by coding one or more unit blocks other than the specified unit blocks. |
