| 摘要 |
The present invention aims to provide the technique of appropriately enabling the encryption and decryption to the partial area with respect to the image data to which the partial encryption and the multiple encryptions have been applied. More specifically, the predetermined image area in the image data is acquired by a reproduction area designation unit, the overlap area of the acquired image area and the encrypted encryption area is calculated by an overlap judgment unit, the key information corresponding to the calculated overlap area is acquired by a decryption key acquisition unit, and the image data corresponding to the overlap area is subjected to the encryption and decryption by an image decryption unit by using the acquired key information. |
