Patent ID: 7447915

Claim:
An on-board map data processing device that handles map data, a portion of the data being encrypted and stored on a portable storage medium, the on-board map data processing device comprising: a holding portion that detachably holds the portable storage medium; and a controller that: decrypts an encrypted portion of the map data that is stored on the storage medium using a code specific to the storage medium, only a portion of the map data that is stored on the storage medium being encrypted; creates an expanded map data to be stored by adding a different map data to the decrypted map data; and stores the expanded map data, wherein the encrypted portion includes at least one of: a region more dense with roads as compared to other regions of the map data; a region more dense with facilities as compared to other regions of the map data; a road larger than other roads of the map data; and a facility larger than other facilities of the map data; the storage medium has the code specific to the storage medium stored therein and the controller encrypts only a portion of the expanded map data based on the code that is specific to, and stored on, the storage medium on which the expanded map data is to be stored.