METHOD OF PROVIDING DIGITAL CONTENTS, METHOD OF MONITORING ILLEGAL USE OF DIGITAL CONTENTS, APPARATUS FOR PROVIDING DIGITAL CONTENTS, AND APPARATUS FOR MONITORING ILLEGAL USE OF DIGITAL CONTENTS

摘要

The digital content supply unit inserts a transaction identifier for identifying a transaction into digital contents as a digital watermark, generates transaction information including license definition information on the usage of the digital contents, stores the generated transaction information in one-to-one correspondence with the transaction identifier, and provides a user with the watermarked digital contents. The digital content illegal use monitoring unit extracts a digital watermark from digital contents, acquires transaction information from a storage by using a transaction identifier contained in the digital watermark, and decides whether or not the digital contents are illegally used, based on license definition information obtained from the transaction information and on the content or form of the digital contents from which the digital watermark is extracted.