In digital data counterfeit detecting program, apparatus, and method, an address arithmetic processing is performed for a value of one of a plurality of digital data which is stored in each of addresses, a result of the address arithmetic processing performed for the value of the one of the digital data representing one of the addresses and a predetermined arithmetic processing is executed for the value stored in each of the addresses which are the respective results of the address arithmetic processing to calculate a collation value used for a digital data counterfeit detection.