To enable a watermark to be inserted in a manner that the insertion cannot be located, to prevent generation of a program working properly without watermark information.
The watermark insertion device generates watermark information from ID information unique to a destination for the program to be distributed, inserts the watermark information into the program, and modifies the watermark information for every distribution destination so that the area near the location where the watermark information is inserted or the entire program cannot be changed by the program specification. Accordingly the program is prevented from working properly, if the watermark information is modified. In addition, a code not different for each distribution destination is inserted in the program to prevent the code for the watermark from being identified through differential attack.
YAMAGUCHI TAKAO
SATO JUNICHI
TAKEI ICHIRO
ITO TOMOYOSHI
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