Patent ID: 7328458

Claim:
An authoring system for authoring content data (Content), comprising: an authoring device; and an authoring key generator including: means for generating a content identifier (CID) uniquely allocated to each of the content data (Content); means for generating an authoring key enabling key (CEK) uniquely allocated to the authoring device for authoring the content data (Content); and means for generating an authoring key (CED) by encrypting a content key (Kc) and a second content key (EKc) with the content identifier (CID) and the authoring key enabling key (CEK), the content key (Kc) being for encrypting the content data (Content), and the second content key (Ekc) being obtained by encrypting the content key with a root key (Kroot); the authoring device including: means for receiving the content identifier (CID), authoring key enabling key (CEK) and the authoring key (CED) from the authoring key generator; means for storing content corresponding to the content identifier (CID); means for storing the content identifier (CID), authoring key enabling key (CEK) and the authoring key (CED); means for decrypting the authoring key (CED) with the content identifier (CID) and the authoring key enabling key (CEK) to obtain the content key (Kc) and the second content key (EKc); and means for encrypting the content data (Content) with the decrypted content key (Kc) to generate encrypted content data (E (Kc, Content)).