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AssigneeCanon Kabushiki Kaisha
InventorsKeiichi Iwamura, Yuji Suga, Junichi Hayashi
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This invention provides an image data encryption technique which facilitates management of access keys in encrypting image data having a hierarchical structure in which the data of each layer can be specified by at least two parameters, and is resistant against exchange of access keys between a plurality of users. To implement this technique, in this invention, in encrypting image data having a hierarchical structure in which a layer is specified by layer and resolution levels, an access key K for the highest resolution and highest layer is set. Access keys are generated by using a one-way function in a direction which the level becomes low. The access key for a given layer can be generated from either of the access keys of layer and resolution located at the higher level. The data of each layer is encrypted in accordance with a corresponding access key.
An image data encryption method of encrypting image data by using key information, comprising:
An image data encryption apparatus for encrypting image data by using key information, comprising:
A computer program which functions as an image data encryption apparatus for encrypting image data by using key information, functioning as:
An method for generating key information used for encrypting or decrypting image data which has a hierarchical structure and in which data of each layer can be specified by at least two parameters, and each parameter is expressed by multilevels, said method comprising;
Dependencies are inferred from the claim text.