| 摘要 |
PROBLEM TO BE SOLVED: To embed ancillary information (second information), such as electronic signatures, by electronic watermarks into main information (first information) composed of a plurality of event data, such as MIDI data. SOLUTION: The event data in the first information composed of a plurality of the event data is classified to >=2 groups (for example, groups by channels). The second information indicating the method for changing the information is inputted and the contents of the event data included in one of these groups are changed in accordance with the second information and, on the other hand, the contents of the event data included in another group different from the one group are changed in accordance with the second information by using a changing method different from this changing method. The second information is thus dispersed and arranged in the first information. The information may be changed in accordance with the second information and third information respectively indicating the different changing methods by each of the respective groups. The second information (further, the third information) is extracted from the first information and is decoded. |
