Method for enabling a file

#1. Field of the Invention

#The present invention relates to a method for enabling a file, which is stored on a storage medium together with at least one other file, for use by a single computer system or by a limited number of local computer systems. The invention also relates to a system for managing and enabling use rights on files.

#2. Description of the Related Art

#FIG. 1 illustrates a system overview;

#FIG. 2 illustrates the file structure for the files;

#FIG. 3 illustrates different variants of the identifier for the file which is to be enabled;

#FIG. 1 illustrates a system overview with a central station 1 and seven computers 2a to 2f of a total of n computers. The computers 2 are local computer systems of a wide variety of types. The computers 2 are connected to the central station 1, not via a fixed line network. However, the computers 2 can contact the central station 1 by means of a telephone connection or Internet connection. This is also not a prerequisite for carrying out the method, however.

#The central station 1 stores the device identifiers ID1 to IDn and also the key k for decrypting the encrypted files and the change vector c for changing the device identifier ID with each enable procedure, in the form of vectors. Each of the local computers 2 stores the individual device identifier ID and also the change vector c. A software package is stored on a CD-ROM and contains a number of programs and databases in a hierarchical file structure. A file management program is also stored on the CD-ROM.

#FIG. 2 shows such a file structure, where the files D01 to D18 may also be file directories and hence contain other files or file directories. In the case of a CD-ROM for a navigation system, the file D01 may be the file directory “Countries”, for example. In this case, the files D02 to D04 may be regional file directories, in particular individual countries. These file directories can be split again, as is the case with the file directory D02, for example, which is split into the file directories D05 and D06. By way of example, D02 may be a country directory “Germany”, and the file directories D05 and D06 may be the file directories for “Northern and Southern Germany”. The respective file directories D05 and D06 then have associated files for the map data D12 and D14 and associated files D13 and D15 containing the associated travel guides.