CONTENTS ENCODING METHOD AND DEVICE, CONTENTS DECODING METHOD AND DEVICE, CONTENTS DISTRIBUTING METHOD AND DEVICE, CONTENTS ILLEGAL COPY CHECKING METHOD AND DEVICE, CONTENTS ENCRYPTING PROGRAM AND ITS PROGRAM RECORDING MEDIUM, CONTENTS DECODING PROGRAM AND ITS PROGRAM RECORDING MEDIUM, CONTENTS DISTRIBUTING PROGRAM AND ITS PROGRAM RECORDING MEDIUM, AND CONTENTS ILLEGAL COPY CHECKING PROGRAM AND ITS PROGRAM RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide a technology for allowing a user side to efficiently embed user information in contents by using an electronic watermark, and for allowing a provider side to prevent the illegal cancel of the embodiment of electronic watermark information or the embodiment of any false electronic watermark information at the same time. SOLUTION: Contents are divided into a plurality of parts, and a plurality of electronic watermarks are prepared for those respective divided parts, and the electronic watermark for each user is acquired by combining the values of the electronic watermarks of the extracted divided parts. Thus, it is possible for the user side to realize configuration that the electronic watermark information specific to the user is embedded in the contents, and it is possible for a provider side to actually control the electronic watermark information to be embedded and the embedding processing. Thus, it is possible to prevent the illegal cancel of the embodiment of the electronic watermark information or the embodiment of any false electronic watermark information at the user side.