Hitachi, Ltd.

Shinichiro Harano

Hiroshi Yoshiura

Ryoichi Sasaki

Isao Echizen

Shinobu Eikawa

Katsuyuki Okeya

In scalar multiplication method in which a point on an elliptic curve is randomized, but yet scalar multiplication can be calculated by the computational cost as much as that without randomization, an operation is carried out upon a point randomized and a point not randomized in a scalar multiplication method to calculate a scalar-multiplied point from a scalar value and a point on an elliptic curve. The result of the operation is randomized while the computational cost becomes as much as that without randomization.

Elliptic scalar multiplication system

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).

Digital watermark data embedding method, and digital watermark data embeddability analyzing method

To enable the control of rendering contents in part by using digital watermark technique: a contents serving center for embedding watermark in contentsembeds 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 centerdistributes the watermark-including contents to a receiving terminalwhere 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.

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Yokohama, Japan

Shinichiro Harano