An application is activated with access permission to resources which are granted to unsigned applications. In parallel with the execution of the application, tamper check is performed on the application using a tamper check thread. When access to a resource which is not granted to unsigned applications is requested during the execution of the application before the completion of the tamper check, the application is put in a wait state until the completion of the tamper check. After the application is judged as having been untampered with as a result of the tamper check, the application is further granted access permission to resources that are specified by a permission information file included in the application. If this further-granted access permission includes the access right to the resource, the execution of the application is continued.