Digital contents distribution system capable of flexibly changing using conditions

A digital contents distribution system comprising:

• an author terminal of an author who creates digital contents;
• a copyright management agency, serving as a deputy of the author, for carrying out copyright management of said digital contents said author creates;
• a digital contents distribution center that distributes said digital contents;
• at least one user terminal that receives said digital contents;
• and
• an information transmission medium that interconnects said author terminal, said copyright management agency, said digital contents distribution center and said user terminal,
• wherein said author terminal comprises link means for generating first execution verify logic that carries out verification and execution control of said digital contents, and for linking said first execution verify logic with said digital contents,
• wherein said copyright management agency comprises execution verify logic conversion software generating means for generating a second execution verify logic in accordance with specifications of said second execution verify logic transmitted from said digital contents distribution center, and for generating execution verify logic conversion software for replacing said first execution verify logic with said second execution verify logic, and
• wherein said digital contents distribution center comprises specifications generating means for generating said specifications of said second execution verify logic, and compare and verify means for comparing said second execution verify logic, which is included in said execution verify logic conversion software transmitted from said copyright management agency, with said specifications of said second execution verify logic, which are generated in said digital contents distribution center, to verify said second execution verify logic, and wherein said digital contents distribution center provides said user terminal with at least part of said execution verify logic conversion software and said digital contents linked with said first execution verify logic, via said information transmission medium.