Method for the transmission of management data

Abstract

This invention relates to a method for the transmission of management data to at least one multimedia unit or a group of multimedia units. This method is characterised in that said management data is sent in the form of at least one authorisation message encrypted by means of at least one synchronisation key (SK), the sending of said at least one authorisation message being repeated cyclically and intended for said multimedia unit or said group of multimedia units, and in that the synchronisation key is modified at least during each cycle.

Description

SUMMARY DESCRIPTION OF THE DRAWINGS

This invention and its advantages will be better understood with reference to the enclosed Figures and to the detailed description of a particular embodiment, in which:

FIG. 1 shows a first embodiment of message sending according to the method of this invention;

FIGS. 2 and 3 illustrate two variants of messages used in the process of the invention; and

FIG. 4 represents schematically message decryption such as illustrated in FIG. 2.

Claims

1. Method for the transmission of management data to at least one multimedia unit or a group of multimedia units, wherein said management data is sent in the form of at least one authorisation message encrypted by means of at least one synchronisation key, the sending of said at least one authorisation message being repeated cyclically and intended for said multimedia unit or said group of multimedia units, and wherein the synchronisation key is modified at least during each cycle.

2. Method for the transmission of management data according to claim 1, wherein said management data contains at least one identifier of the synchronisation key.

3. Method for the transmission of management data according to claim 1, wherein said management data contains at least the synchronisation key.

4. Method for the transmission of management data according to claim 1, wherein said management data is access rights to data, keys, an executable code and/or management data of the multimedia unit.

5. Method for the transmission of management data according to claim 1, wherein the synchronisation key is sent at the beginning of a cycle.

6. Method for the transmission of management data according to claim 1, wherein the authorisation messages are encrypted only with said synchronisation key.

7. Method for the transmission of management data according to claim 1, wherein the authorisation messages are encrypted on one hand with a key called an authorisation key and on the other hand with said synchronisation key.

8. Method for the transmission of management data according to claim 7, wherein the authorization key is not modified according to the modification frequency of the synchronisation key.

9. Method for the transmission of management data according to claim 7, wherein the encryption of the authorisation messages is carried out firstly by means of said authorisation key and secondly by means of said synchronisation key.

10. Method for the transmission of management data according to claim 7, wherein the encryption of the authorisation messages is carried out firstly by means of said synchronisation key and secondly by means of said authorisation key.

11. Method for the transmission of management data according to claim 1, wherein said synchronisation key is modified after the encryption of a determined number of authorisation messages, this number being lower than or equal to a number of messages forming a cycle.

12. Method for the transmission of management data according to claim 1, wherein said synchronisation key is modified after a determined usage duration, this duration being lower than or equal to the duration of a cycle.

13. Method for the transmission of management data according to claim 1, wherein said synchronisation key is made up of several parts of the synchronisation key and in that said key parts are transmitted to the concerned multimedia units in several different messages.

14. Method for the transmission of management data according to claim 13, wherein said different messages containing a part of the synchronisation key are of at least two different types.

15. Method for the transmission of management data according to claim 1, wherein said authorisation message contains a time information.

16. Method for the transmission of management data according to claim 1, wherein said authorisation message contains a unique value different for two different messages.

17. Method for the transmission of management data according to claim 1, wherein at least two synchronisation keys are used simultaneously.

18. Method for the transmission of management data according to claim 17, wherein the synchronisation keys have a different validity duration.

19. Method for the transmission of management data according to claim 1, in which said at least one multimedia unit contains an identifier and in which at least one broadcast message contains at least one identifier serving to indicate for which multimedia unit this message is intended, wherein said identifier contained in the message is encrypted by the synchronisation key.