A navigation system with decryption functions. The navigation system may receive from a portable data storage medium an encrypted authentication key, an encrypted first portion of a geographic database, and an unencrypted second portion of the geographic database. The navigation system may then decrypt...http://www.google.co.uk/patents/US7640595?utm_source=gb-gplus-sharePatent US7640595 - Computing system with decryption functions and secure data product
