Patent ID: 7328178

Claim:
A content billing method for performing billing processing for digital content in which identification information is embedded by using a digital watermarking technique on a computer, comprising the steps of: (a) searching for a plurality of digital content items, and collecting information on whether or not the plurality of digital content items exist; (b) extracting identification information embedded in advance in the plurality of digital content items, and generating and recording use information on the plurality of digital content items based on the identification information; (c) recognizing a status of use in a predetermined period based on comparison of the newest use information and older use information which is recorded, and generating state-of-use information, when a digital content item having first identification information identical to second identification information of a previously detected digital content item is newly detected, the newly detected digital content item is determined to be a copy of the previously detected digital content item; and (d) calculating a use fee for digital content according to the state-of-use information and referring to a fee table provided for each digital content item and calculating a use fee corresponding to the copy.