Patent ID: 6963655

Claim:
A contents alteration detection apparatus having a data filling apparatus and a detection apparatus, said data filling apparatus filling certain embedding data to contents data being objective to embed said embedding data, said detection apparatus detecting whether alteration was added to said contents data or not, said data filling apparatus, comprising: a contents data dividing means for dividing at least a part of said contents data into a plurality of first data blocks, each first data block containing a plurality of unit data; and a data filling means for filling each of certain first embedding data to each of said divided first data blocks to generate a plurality of second data blocks, the second data blocks having a modified relationship, relative to the first data blocks, between values of a corresponding plurality of said unit data in adjacent second data blocks according to a predefined rule, said detection apparatus, comprising: a data extracting means for extracting said second embedding data filled in each of at least a part of said second data blocks to obtain second embedding data; and an alteration detecting means for detecting whether or not alteration was added to each of at least a part of said second data blocks based on said extracted second embedding data having the modified relationship according to the predefined rule, and an altered position indication means for analyzing the second embedding data relative to the first embedding data to determine for each of the second image blocks, whether changes were made in said each of the second image blocks for indicating the positions occupied by said second image blocks of which added alteration was detected.