Patent ID: 7185369

Claim:
A motor vehicle navigation or multimedia computer system comprising: a central processor with associated memory and a manual input unit; an output unit and a reader for a bulk storage medium, wherein the navigation or multimedia system has means for checking authorized use of each of the bulk storage medium and a selected file from a group of files on the bulk storage medium; a file management system which is designed to compare an access authorization identifier to enable access to the selected file from a group of files, calculated from a code entered using the manual input unit with access authorization identifiers for the files stored on the bulk storage medium; a means for unscrambling an access authorization identifier entered in scrambled form; means for calculating a key (k) decrypting an encrypted file from a first code (PIN) stored on the storage medium, entered in scrambled form, and a stored device identifier; and means for calculating the access authorization identifier (AC) from a second code (ACW), entered in scrambled form using the key (k).