An example of a device comprises a storage which stores data which is input from outside and to which tracking information is added, a section which detects a first reading event of first data from the storage to which the tracking information is added, a section which detects, after the first reading event, a first writing event to part of character string data to the storage, a section which detects, after the first writing event, a second reading event of second data from the storage to which the tracking information is added, a section which detects, after the second reading event, a second writing event to part of the character string data to the storage, and a section which adds, when the first reading/writing event, second reading/writing event are detected, the tracking information to data to be written to the storage by the first and second writing event.