Patent ID: 6912512

Claim:
A digital contents distribution system comprising: an author terminal for transmitting digital contents; a copyright manager for carrying out copyright management of said transmitted digital contents; a distribution center for distributing said digital contents and receiving requests for a different degree of access to 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 manager, said distribution center and said user terminal, wherein said author terminal comprises link means for generating a first logic scheme for verification and execution control of said digital contents, said link means linking said first logic scheme with said digital contents, wherein said copyright manager comprises a logic conversion software generator generating logic conversion software including a second logic scheme in accordance with specifications of said second logic scheme transmitted from said distribution center for replacing said first logic scheme with said second logic scheme upon execution by said user terminal, the second logic scheme providing the user terminal with a different degree of access to the digital contents than the first logic scheme, thereby precluding said distribution center from changing the degree of access to the digital contents granted to the user terminal without first receiving said logic conversion software from said copyright manager, and wherein said distribution center comprises generating means for generating said specifications of said second logic scheme when said distribution center receives a request for a different degree of access to said digital contents, and an evaluator for comparing said second logic scheme, included in said conversion software transmitted from said copyright manager, with said specifications of said second logic scheme, generated in said distribution center, to verify said second logic scheme, and wherein said distribution center provides said user terminal with at least part of said conversion software and said digital contents linked with said first logic scheme and said conversion software, via said information transmission medium.