The invention relates to a navigation installation having a broadcast radio receiver for extracting information transmitted in encrypted form, particularly traffic information, from broadcast radio signals, having a navigation unit and having a data storage medium reading unit.

The invention also relates to a method for extracting information transmitted in encrypted form from broadcast radio signals with a navigation installation.

To enable encrypted data which are transmitted by means of broadcast radio signals and which can be used only in return for a fee, it is known practice to provide the user with a license key. This can either be input manually as an access code or can be provided as a key record on a data storage medium for the purpose of executing a decryption algorithm.

Thus, by way of example, in order to use pay televisions, the users are provided with access authorization memory cards which, in conjunction with a video data decoder, allow an encrypted broadcast radio program to be decrypted.

To protect data and software which are stored and sold on a data storage medium against unauthorized use when unauthorized pirate copies have been produced, it is known practice to produce an access code comprising a license key and a license number stored on the data storage medium. Alternatively, the license number may be requested from the data supplier by telephone or using a computer network by indicating the license key which is printed on the data storage medium. The access code is then stored and allows the installed data, for example in the form of software, once enabled, to be used without requiring renewed authorization.

With knowledge of the license key and possibly of the enabling code, however, it is also possible for any third party to use the data in conjunction with an unauthorized copy of the data on a copy data storage medium.

It is also known practice to calculate the access code from a combination comprising a license key with the serial number of the data processing device processing the data. This has the drawback for the user that the inherently authorized data storage medium can be used only in conjunction with a single data processing device which the user stipulates when the data are enabled for the first time.

It is an object of the invention to provide an improved navigation installation having a broadcast radio receiver for extracting information transmitted in encrypted form from broadcast radio signals in which the enabling of individual added-value services which are subject to a charge, particularly of traffic information transmitted in encrypted form, has optimum protection and can easily be managed.

The object is achieved with the navigation installation of the type mentioned at the outset by virtue of the navigation unit being set up to read decryption data which are stored on a data storage medium with the data storage medium reading unit and to extract encrypted information using the decryption data which have been read.

Storing decryption data on the data storage medium which is provided for operating the navigation installation anyway and which contains map material, for example, allows simple control of the enabling of added-value services.

The data storage medium can be provided with the decryption data at the factory itself, the user being billed for the added-value services when the data storage medium is actually purchased.

Replacing the data storage medium allows possibly different added-value services to be used depending on the respective decryption data which the data storage medium contains. These added-value services can be used in conjunction with the individual data storage medium in different navigation installations, since the decryption data are stored on the data storage medium and hence are independent of the navigation installation.

It is particularly advantageous if the decryption data comprise a decryption algorithm. This decryption algorithm can then be called by the navigation installation without the need for said navigation installation to be designed per se particularly for decrypting the information transmitted in encrypted form.

Storing the decryption data, including optionally the decryption algorithm, on the data storage medium has the advantage that the data storage medium can easily be updated using a computer network, for example the internet. It is thus possible for access authorization to be obtained over the internet by a provider, who subsequently sends the decryption data to the user, who stores these data on the data storage medium.

Extraction of the encrypted information may also be simple enabling of the use of added-value services on the basis of decryption data.

The object is also achieved by a method for extracting information transmitted in encrypted form from broadcast radio signals with a navigation installation as described above, by virtue of

- d) a data storage medium number which is allocated by the manufacturer of a data storage medium and which is stored unalterably on the data storage medium being read from the data storage medium,
- e) an access code which is required for extracting the information being generated from the data storage medium number and from a license number, and
- f) the information being extracted if the access code is admissible.

Coupling the enabling of the added-value services to an unalterable serial number for the data storage medium, which serial number is allocated by the manufacturer of the data storage medium, provides protection against use of the added-value services in conjunction with an unauthorized copy of the data storage medium. This makes use of the fact that conventional data storage media are normally supplied with a data storage medium number which is allocated by the manufacturer and which is stored such that it cannot be manipulated. This data storage medium number can easily be read and serves as a basis for calculating an access code.

By way of example, the data storage medium number may be used in conjunction at least with a license number which is allocated individually for the supplied data storage medium and which does not need to be secret. Thus, the license number may be printed on the data storage medium's packaging or on the data storage medium itself, for example, or may be stored in the data storage medium in readable form.

In this connection, it is advantageous if the license number allocated for an original data storage medium is read from the data storage medium.

It is also advantageous if a record stored on the data storage medium, comprising at least a license number and an access code, and also the data storage medium number stored unalterably on the data storage medium by the manufacturer of the data storage medium are read. The license number and the data storage medium number are used to generate an access code which is compared with the stored access code in order to enable extraction of the information.

The access code is calculated using inherently known algorithms, for example secure hash algorithms. The access code can be used to operate a decryption algorithm, provided on the data storage medium or in the navigation installation, for example, for decrypting encrypted data.

It is also advantageous if a serial code for the navigation installation is read and the information is extracted on the basis of the serial code. This restricts the access control for added-value services to one particular navigation installation.

The invention is explained in more detail below using an exemplary embodiment with reference to the appended drawing, in which:

FIG. 1 shows a sketch of a navigation installation.

FIG. 1 shows a sketch of a navigation installation 1 with a display unit 2 in a housing 3 for showing the routing. The navigation installation 1 can be operated wirelessly and/or by wire using a remote control, for example.

The navigation installation 1 is connected to a position-finding unit 4 and to a broadcast radio antenna 5. At least the broadcast radio antenna 5 is routed to a broadcast radio receiver 6 in the navigation unit 7, said broadcast radio receiver being set up to extract traffic information from broadcast radio signals received using the broadcast radio antenna 5.

The navigation installation 1 also has a data storage medium reading unit 8 for data storage media 9 which store navigation data, particularly map material, for routing.

To enable the use of added-value services and particularly to use encrypted traffic information, which provides information going beyond the freely accessible traffic information in the form of TMC services which are subject to a charge, it is proposed that decryption data ED be read from the data storage medium 9 with the data storage medium reading unit 8 and that the added-value services be enabled on the basis of the decryption data ED.

In this case, a decryption algorithm can also be read from the data storage medium 9 and can be executed in the navigation unit 1 in order to decrypt the traffic information transmitted in encrypted form and other added-value service information.

The added-value services can be enabled in conjunction with a data storage medium number which is allocated by the manufacturer of a data storage medium 9 and which is stored unalterably on the data storage medium 9. This number is read from the data storage medium 9 by the navigation unit 7 using the data storage medium reading unit 8.

The data storage medium 9 may additionally store at least one access code. When the data storage medium number has been read with a suitable algorithm, for example a secure hash algorithm, the navigation unit 7 generates an access code which is compared with the access code stored on the data storage medium 9.

In addition, the access code can be produced in conjunction with a license number which is allocated individually for the user or for the data storage medium 9. The access code is then generated and checked with a suitable algorithm from the combination of the data storage medium number and the license number.

The decryption data ED may be stored on the data storage medium 9 at the factory itself. Alternatively, it is possible to update the data storage medium 9 and to acquire a possibly time-limited authorization to use added-value services over a global computer network, e.g. the internet, for example. The global computer network is then used to provide the decryption data ED to the user for storage on the data storage medium 9. A data storage medium 9 of this kind may be a compact flash memory card, for example.