DATA PROCESSING APPARATUS AND METHOD THEREOF

摘要

By successively converting a particular key by one-direction function, it is possible to generate different keys corresponding respective hierarchies of image data having a hierarchical structure. Image data of each hierarchy is encrypted by using the generated key. By generating keys using one-direction function, it is possible to generate a key corresponding to image data of lower hierarchy from a key corresponding to image data of upper hierarchy but it is impossible to generate a key corresponding to image data of upper hierarchy from a key corresponding to image data of lower hierarchy. Thus, when performing access control to the image data having a hierarchical structure, it is possible to easily manage keys.