Patent ID: 8281362

Claim:
A verification method used in an information processing device that executes processing relating to playback of contents by using a virtual machine included therein, the verification method using a storage medium having content, a verification program, and a verification rule table in correspondence with each other stored thereon, the verification rule table including one verified address range and one verification rule in correspondence with each other, the verified address range indicating a range of a memory address of a memory in the information processing device, the verification rule indicating whether verification succeeds by judging whether data held on a storage position in the information processing device indicated by the verified address range corresponding to the verification rule includes a value equivalent to property information of a file constituting the content, and the information processing device holding the property information on the storage position indicated by the verified address range, the verification rule table further including verification values in a one to one correspondences with verification rules and further includes verification timings in a one-to-one correspondence with the verification values, said verification method comprising: reading the content, the verification program, and the verification rule table stored on the storage medium; verifying, by using the virtual machine executing the verification program, legitimacy of the information processing device including the virtual machine; and suppressing playback of the content when a result of the verification indicates that the information processing device is illegitimate, said verifying comprising: generating a random number at each of the verification timings and storing the generated random number at a predetermined address; acquiring, by the verification program, a value held at the memory address indicated by the verified address range in the information processing device; further acquiring, by the verification program, verification information by reading the stored random number at the verification timing; judging, whether the held property information and the value acquired from the memory address indicated by the verified address range in the information processing device satisfy the verification rule corresponding to the verified address range, further judging, whether the random number differs from a comparison of the stored random number in order to determine the information processing device as legitimate; said verifying judges that the information processing device is legitimate by judging that the verification rule is satisfied.