Patent ID: 7965599

Claim:
An information recording medium on which a data group is recorded, the data group including: content data; handling control data for indicating whether or not the content data is encrypted; and a check program for making a reproducing apparatus function as a check apparatus, which checks a state of the handling control data to thereby check whether or not the encrypted content data is illegally decoded, by reading the check program into the reproducing apparatus for reproducing the content data, wherein the data group is divided into a plurality of sections, the handling control data is provided in each of the sections, the check program comprises: a calculation process routine for performing a predetermined calculation process by using a plurality of handling control data, each of which is provided in respective one of the sections; a comparison routine for comparing a result of the calculation obtained by the calculation process routine with a predetermined value; and a restriction executive routine for restricting, stopping, or forbidding the reproduction of the content data if the handling control data is not the predetermined state, on the basis of a result of the comparison by the comparison routine.