Map data processing method, map data processing device, storage medium, and on-board map data processing device

摘要

A map data processing method for handling map data stored in a portable storage medium includes the steps of encrypting only a portion of the map data to be stored on the storage medium, and storing the map data, of which only the portion has been encrypted, on the storage medium. According to this processing method, it is possible to reduce the time necessary for encryption and decryption. In addition, by both encrypting and decrypting the map data based on a code specific to the storage medium, it is possible to minimize illegal copying of the map data.