The present invention offers an electronic device that reduces the amount of data for communication required when files pertaining to software are to be updated, as compared to the conventional devices, and performs tamper detection. The present invention is an electronic device having an application file pertaining to an operation of application software and updating the application file via a network. The electronic device (i) stores therein the application file including one or more data pieces, (ii) receives, from an external apparatus via the network, update data and location information indicating a location, within the application file, which is for rewrite with the update data, (iii) rewrites only part of the application file by writing over a data piece present at the indicated location with the update data, to update the application file, and (iv) examines whether the updated application file has been tampered with.