Patent ID: 8656173

Claim:
A non-transitory computer-readable medium having recorded thereon an electronic image data verification program that causes a computer to execute a process comprising: dividing electronic image information into a plurality of blocks; transforming the electronic image information into another electronic image format for lossy compression so as to generate transformed electronic image information; generating partial signature information indicating signature information for each of the plurality of blocks of the electronic image information by applying a hash function to first intermediate information of the plurality of blocks where image information of each of the plurality of blocks is not influenced by image information of other blocks, the first intermediate information being obtained in an intermediate process of format transformation by the transforming and not being influenced by lossy compression; registering the transformed electronic image information and the partial signature information; decoding the transformed electronic image information which is registered by the registering; generating partial signature information for each of the plurality of blocks of the transformed electronic image information which is registered by the registering, by applying the hash function to second intermediate information, the second intermediate information being obtained in an intermediate process of the decoding, a phase when the second intermediate information is obtained in the decoding corresponding to a phase when the first intermediate information is obtained in the format transformation; and verifying, by utilizing the partial signature information for each of the plurality of blocks of the transformed electronic image information and the partial signature information registered by the registering, presence or absence of a change to the electronic image information, or a changed portion when the change has been made to the electronic image information, wherein the registering includes: providing an electronic signature of a person who has made the change to the electronic image, to transformed electronic image information generated by transforming the changed electronic image and the partial signature information corresponding to the changed electronic image so as to register them, and the verifying includes: verifying that the change has been made by the person, based on partial signature information corresponding to electronic image information prior to the change, partial signature information corresponding to electronic image information after the change, and the electronic signature of the person.