A burden caused by handling a large number of unique identifying information pieces such as authentication keys is to be lightened from both the user side and the protector side such as application creators. A proof data verification device sends authentication data to a proof data generation device. The proof data generation device generates proof data from both received authentication data and user unique identifying information held therein and sends it back to the proof data verification device. The proof data verification device holds an access ticket and authentication data, and verification means in the verification device performs a signature verifying calculation by use of the proof data, authentication data, and the access ticket. If the verification is successful, the execution of program is allowed.