Apparatus and method for preparing modified data to prevent unauthorized reading/execution of original data

摘要

An apparatus for preventing unauthorized reading/execution which does not necessarily require an extra storage region, but controls adverse effects to operating environment such as OS or the like, and contributes to restricting diffusion or distribution of unauthorized copies. An original CD-ROM readable by a driver stores original data, which in part contains modified data of a different value from a predetermined value to be generated by the driver. A copied CD-ROM stores copied data of the original data, and data of such predetermined value as generated by the driver at a time of making the copy. To prevent execution of data that is to be read by the driver, an apparatus for preventing unauthorized reading/execution (181) is provided with a modified data detecting unit (182) capable of detecting modified data from the data stored in the original CD-ROM or the copied CD-ROM, and a copied CD-ROM performing unit (195) for preventing execution of data by read-out of the driver, in response to failure of detecting the modified data by the modified data detecting unit (182).