Abstract: A method of embedding digital watermark information b1–bn (2?n) in image data. The image data is divided into a plurality of areas S each consisting of M×N (1?M, N) pixels. A plurality of areas G each consisting of P×Q (1?P, Q) of the areas S are defined. Each of the areas S constituting each area G is allocated to some one of: areas T1–Tn in which said digital watermark information b1–bn is respectively embedded and areas H1–Hm (1?m) in which information is not embedded. One or more areas T and one or more areas H are located in a predetermined arrangement in each area G. And, the plurality of areas G are located in a predetermined rule.

Abstract: To lighten the processing load of embedding a digital watermark in content data, a preliminary process (embedding strength map generating process) run by a preprocessing section and the main process (digital watermark embedding process) run by a man processing section are run mutually independently. Specifically, the preliminary process of the preprocessing section is run each time new content data is stored to the content data database, and the main process of the main processing section is run when a content delivery request is received from a receiving terminal (client).

Abstract: To enable the control of rendering contents in part by using digital watermark technique: a contents serving center for embedding watermark in contents 4 embeds control information as digital watermarks within at least one of a plurality of blocks constituting electronic data by which contents are represented, thereby specifying the application of filtering to a part of the contents corresponding to the block; a contents distribution center 1 distributes the watermark-including contents to a receiving terminal 2 where checks the blocks of the received data to detect whether the control information as digital watermarks is embedded therein and applies the filtering to the block for which the embedded control information embedded has been detected in advance of reproducing the contents.

Abstract: There is provided a steganographic system which can dispense with an original image during extraction of watermark by determining a position at which an optimum space dependent physical quantity is embedded as a watermark complying with an image such that the picture quality can be prevented from being deteriorated, embedding watermark information in the image, generating information such as watermark embedding position information and receiving a watermark embedded image and watermark embedded position information to extract watermark information.

Abstract: To lighten the processing load of embedding a digital watermark in content data, a preliminary process (embedding strength map generating process) run by a preprocessing section and the main process (digital watermark embedding process) run by a man processing section are run mutually independently. Specifically, the preliminary process of the preprocessing section is run each time new content data is stored to the content data database, and the main process of the main processing section is run when a content delivery request is received from a receiving terminal (client).