PROBLEM TO BE SOLVED: To provide an information distribution system capable of preventing unauthorized copying. SOLUTION: The invention is an authoring system that conducts authoring by encryption for copyright protection for content data distributed via an information distribution terminal 400. An authoring key generating device 160 generates a content identifier (CID) uniquely allocated to each content data, an authoring key usage key (CEK) uniquely allocated to each authoring device that conducts authoring for content data, a content key (Kc) used in encryption of content data, and an authoring key (CED) obtained from encryption of a second content key (EKc) using CID and CEK. The second content key (EKc) is derived from encryption of the content key by a root key (Kroot). An authoring device 316 is provided with a decrypting means for decrypting CED to get Kc and Ekc using CID and CEK, and an encryption means for encrypting content data using the decrypted Kc to generate an authored and encrypted content data (E (Kc, Content)).
展开▼